Time to tackle the thick of this bear. Zangief, I hope you taught me well.
SpoilerAnimal Companion is solidly good for the same reasons it's good for a Druid. I would maybe decrease it down to BW Level-3, minimum one. If a BW really wanted to, then they could spend a feat to get it up to their character level.
The Arctic/Desert Adaptation is also interesting. I would, however, mention that you gain all of the lesser abilities if you spend more BP. This way, you've got the Endure Effect up at all times even if you went a little heavy to get energy resistance.
Calm Animals is a little underwhelming as the only effect. May add something else? Not too sure there.
You may want to turn "Catfall (Su)" into Catfall (PLA). Also, you have it as "instant action" where I think you mean immediate.
For Climb Like a Monkey, why not just give them a Climb speed? I'd probably just throw that on there for 1 or 2 BP for 24 hours, in addition to the base effect.
Discern North is near worthless. All characters with 5 ranks in Survival can do that for free.
Healthy as a Horse is also kind of underwhelming. It's not stated, but I'm inclined to assume it protects against magical diseases as well.
Hide from Notice doesn't do much. If it wasn't for the fact that this is a first level ability, I would almost suggest throwing Hide in Plain Sight on top of it. As is, maybe also let it boost Move Silently checks instead?
Jump Like a Rabbit feels like the rest of the skill boosters to me, sadly. Not sure what additional feature to throw here, though.
Keen-Eared feels much like the rest, too. May throw on Spot checks too?
For Lesser Scent, do you just mean Scent? RAW, I am not familiar with anything called Lesser Scent. Other than that, looks fine.
For Move Like a Cat, I'd maybe include some of the benefits of the Balancing Lorecall spell (Spell Compendium) if extra BP are used.
Natural Armor feels like something to grab when nothing else strikes your fancy. Basically a free feat, so, not bad.
I love Plating, but you need to clarify the initial Max Dex restriction on it. As is, it sounds like you start with NI Max Dex for the first cost, then go down to -1 Max Dex, which is silly and a little counter-intuitive. I also like how the extra BP further increase the duration.
Quiet as a Mouse: see my comments on Hide from Notice. If you don't merge them, not sure what to add here.
Savagery I: I'd almost want to say "add +1d4 damage..." for the next round with your natural weapons. It'd be a little extra incentive to take this for those guys who grabbed claws or tentacles is all. Otherwise, it shouldn't be an issue as it is a first level power.
Mix Serpent Blooded with Healthy as a Horse maybe? Poisons are probably more likely to show up than diseases, but bonus to one usually come with bonuses to the other.
Sharp-eyed: see keen-eared. Again, no clue what a "secondary" effect would be here.
Slippery as an Eel is like the rest of its kin. A bonus to grapple checks may also be a good idea for higher BP costs.
Swim like a Fish: see Climb Like a Monkey.
Track is a little underwhelming. In the case of Natural Armor, you're getting either an epic feat (not really) or an otherwise difficult to qualify monstrous feat (assuming you don't already have a natural armor score of at least +1).
Venom looks okay, but it needs an initiation action. I also feel that, without some significant bonuses for having a higher wisdom score, the use of wisdom over constitution for the save feels forced. May just be me. This ability is missing the initiation action, however. Is it standard, move or swift?
Wild Empathy feels kind of like Track. Doesn't really do much, but may be used to get into an odd PrC or two. Other than that, it feels like filler.
The insane amount of skill boosters here kind of saddens me, especially without some sort of additional benefit other than +more. Factoring the fact that this guys can get pretty high DCs for just a little bit extra makes them look like chumps compared to Incarnum-users who get to throw around their similar skill boosting levels for free all day without locking them out of combat abilities.
As is, it looks like a level 1 Beast Warrior would grab Animal Companion at first level and then kind of not have any other class features. A simple remedy would be to give them 3 instead of 1 ability at first level, then go back down to 2 for the remaining level. Basically every system in DND operates like that. Martial Adepts get 3-6 maneuvers at first level, then down to just a few every other level afterwards. Incarnates and Totemists (Soulborns don't count) get a few soulmelds for the day to start before gaining more. You get the idea.
Endurance is a feat. Also a bland one, but, it does open the door to Steadfast Determination... except you actually would probably have an acceptable Wisdom score. Maybe throw Diehard on here, too. Not like it's going to overpower someone.
Fast Movement looks fine if other abilities start to provide some skirmish capabilities.
Woodland Stride is okay. Not a terribly good or bad class ability, just kind of there.
SpoilerAnimal Affinity is probably good as an insight bonus, considering that once you choose a power, it's there for life.
Bestial Roar should probably have it's save be 10+Half Level+Wisdom modifier instead of being based on the skill check. I still kind of question the large amount of points needed to gain the better effects, but having a fear effect option is nice. This does need a duration on how long the fear lasts and you should probably change "Intelligent creatures" to either "any creature with an Intelligence score" or "any creature with an Intelligence score of 3 or greater."
Ferocity is like a more limited Die Hard. It may be passable if you can continue functioning even passed -10 HP, but with restrictions akin to the Rage Claws soulmeld on just how far down you can go.
Improved Grab/Trip are both solid, as Int feels like one massive dump stat here. I approve!
Natural Weapon looks like a solid ability, but you may want to apply the same restrictions on when you can retake it that you did with a few of the other abilities. Also, you can go ahead and drop "instant" from this sentence "You may manifest all of your natural weapons with the same instant action." Other than that, I would suggest having the first time you take this ability make all of your natural attacks, current and future, magical. Not necessarily give them a bonus a la magic fang, just magical. Otherwise, DR may hurt.
Pounce looks fine, just change the language to say "You gain the pounce ability" and your golden.
Shocking should probably either be a lower action or last longer than just one use, kind of like what I suggested for venom.
Speak with Animals feels like another filler ability, but, hey, now you know how Comrade Bear really feels about the rest of the party.
Trackless Step is just another copied ability. Not much to say here
See some my comments on "Lesser Scent." Really, though, Scent can be a first level ability, considering ToB. You may want to switch this to limited blindsense.Spoiler
Hold Breath, click here for its normal wording.
Beast Form looks fine. I'm inclined to increase the options to "any medium or smaller animal form, chosen when this ability is activated." A bit of a can of worms, but certainly better than Polymorph.
Ooooh, I like Circle the Herd. However, I would either remove the DC 21 to it and make it just opposed by Sense Motive or vice versa. Giving people attacks is nice, even if they are techincally AoOs.
For Larger than Life, I'd go ahead and just make it an actual size increase, rather than giving Powerful Build Lite. Wizards have had Enlarge Person for ages now, so why don't you?
For Rend, the damage is usually 2x base claw damage +1(Maybe 1.5x?)Str mod. Also, it should be "2 or more claw attacks" for those out there for more than the usual amount of arms.
Spines looks okay. The bonus to natural armor feels a little weird, but it's not a bad thing. I would also allow an option to shoot the spines as ranged attacks, but only every other round, as the spines "regrow." If you go that route, maybe even through on a bigger attack with them, but at the cost of losing the benefit for a little while (1d4 rounds).
Sprint is a little underwhelming to me. Feels like filler. Not sure what to do with it, though. With some decent ranged options, it does open the option to kite enemies.
Wolf Pack Tactics looks nice. I'd maybe have it progress such that "Any allies that also threaten the same enemies as you are treated as flanking for all purposes. If they would normally be flanking with you without including the benefits of this ability, increase their to-hit bonus from flanking by +2." Maybe also decrease time needed for the AoO option.
I'm inclined to make Flight a 24-hour ability, with or without making it (Su) in nature. Warlocks have Fell Flight, so why not help the Beast Warrior save on points.
Claw of the Warrior. That would help out slightly with the language, but, if you want it as is, it would mean having three attacks at X, X-5 and X-5 rather than X, X-5, and X-10. I'm not sure which would be better, as one option would let you have more attacks sooner, while the other offers the secondary attacks a greater chance of landing. I'm more inclined to the former, considering the second time you would take this ability is at 20th.
If you take my suggestions for Lesser Scent, Scent, then I would either make Blindsense Blindsight or just make this Blindsense last 24 hours instead.
Savagery II: See comments on Savagery I. Nothing further to add here.
Commune with Nature is an okay spell, but it's primary users have had it for five levels now, which is kind of sad here. Not sure what else could go here in addition to it or instead.
I'd just change Improved Extra Natural attack to granting Multiattack instead. Hell, on top of that, I'd also either decease the level of it or also have it give Improved Multiattack (No penalty for using multiple natural attacks, but I think it's a little tricky to qualify for.) You may want it to only give Improved Multiattack if the Beast Warrior already has Multiattack, though. *shrug*
Greater Extra Natural Attack is basically Improved Multiattack, but only at 20th level.
Supreme Savagery feels a little underwhelming by this point. I would probably increase the base extra damage to +4d10, maybe even +6d10.
Overall, the class doesn't seem like it can actually provide in the skirmisher role, like you suggest: it just doesn't have anything to do at range. The higher level abilities seem a little lacking in number, but that's understandable for a work in progress. I would also go ahead and include a general option for all abilities with an activation of "one standard action" to become swift actions, either as a feat or as extra BP, like some already are.
Other than that looks good so far. It's a little weaker than the Psychic Warrior, due to the issue at lower levels with the skill checks and the low amount of options at higher levels. Still, not bad for a first (or is it second) draft.