First off I should mention that the balance point for this class is supposed to be Tier 1. So it IS supposed to be strong and able to compete with clerics and wizards. Still I do think I went a bit overboard.
On your comments:
Chassis: It's skills are a bit better and I didn't feel it should be a martial class. Its not quite the same as the cleric as it doesn't have access to any armor heavier than light.
Spells: Eh I honestly might just remove the first ability. I initially thought it would be an interesting fluff ability but it seems a bit clunky now and I need to weaken the class anyway. Also for the reason that the spell list isn't arcane while ignoring arcane spell failure is that I didn't want them producing scrolls. With their ability to learn spells from an entire school and cast spontaneously they could give a wizard ally almost any spell they want from the Divination, Necromancy, Conjuration or other schools.
Spirit Channeling: Thanks for wording corrections, sometimes I am not quite clear with my words. The main inspiration was a point based system similar to the Spirit Shaman. The reasons for the school choices were this, Necromancy (Obvious), Conjuration (Summon Undead + Teleport), Divination (Seemed to fit the fluff of calling on spirits. Ask for their help/knowledge). I personally dislike the transmutation school so yes that was an intentional omission. Though to be honest I didn't realize it was the ONLY school I omitted. I probably will remove enchantment as this class has enough ways of getting minions.
On the overpowered aspect I can agree. I wanted a system where the caster had limited sustainability compared with other casters (This class has tactics to make up for it). And to be able to increase their versatility in exchange for their sustainability and vise versa. I think I will cap it at 3 spells called each day for each level, the same as the Spirit Shaman. I also will move divination to the extra school section. So they only start with Conjuration and Necromancy and can select either, evocation, divination, illusion or abjuration.
On the areas of death: Yes it makes it more complicated and a bit harder to balance. As you could have a campaign with an incredibly high death rate from a plague or similar and make this class's power skyrocket. I think I shall add a note that says the DM can ignore this section if it would unbalance a particular campaign.
Soul Harvest: It doesn't check wether creatures have class levels or not so not sure why a being having or not having class levels would matter It gives the Spirit Points based on the Shade Channeler's class level thus a 4th level Shade Channeler gains 2 spirit points per each death to a maximum of 4 in one round. I will however, add a clause preventing the Shade Channeler from killing bags of rats to for this.
Corpse Crafter: The feat doesn't have prerequisites so it didn't make a difference.
Undead Tactics: Ya I should of clarified. You can use a horde tactic in round 1 and then have to wait 5 rounds to use another horde tactic. Then in round 2 you can use a commander tactic and wait 5 rounds till you can use another commander tactic. I will clarify.
Spirit Boons: I meant that at 4th they can only have 1 applied at a time. I will clarify
Efficient Control: "He" is supposed to be the Shade Channeler. Assume a 6th level Shade Channeler attempts to rebuke a ghoul (2 HD 2 Turn Resistance). The Shade Channeler can treat the ghoul as having 1 less HD (Thus 1 HD 2 Turn Resistance or 2 HD 1 Turn Resistance) and would thus command the ghoul. Also the ghoul would only take up 3 HD in the Shade Channeler's Command Undead Pool instead of the normal 4. If someone else attempted to turn or rebuke the ghoul it would still be treated as if it has 4 HD. Does that make it clearer?
Horde Empowerment: Hm, I don't honestly see a problem with switching the amount of undead he can control. I should clarify that if he has more undead under his control then his pool allows he loses the excess undead. Its mainly there to help someone who wants to specialize in skeletons and zombies or commanded undead.
Bonus Feat: Yes I will add that part.
Aspect of Death: Hm, I would normally argue that the ac bonus doesn't matter that much as its a common type. But since I need to weaken the class anyway and it is just a boost I will weaken it. The fort save one will probably stay though, as at 18th level (I will clarify thats when you get the ability) the Shade Channeler will more than likely be undead (And thus lose his constitution modifier).
Transfer Target: Perfect version of dispel magic not sure what you mean by that. It only works on targeted spells (not rays and the like).
Alternate Cost: Its 6 X Spell Level. I will note this.
Custom Horde: I will fix the wording issues. Also good point on the uselessness of greater create undead. I shall make it so that any undead higher than a certain CR will only be able to be animated by greater create undead.
Dread Army: Zombies stop being effective around this level. Also this doesn't really work on any humanoid creature or a creature with class level. I don't think summoning a temporary stone giant zombie is worth a 7th level spell. As summon monster VII can create a bone creature that can cast wall of ice, dimensional anchor, fly, major image all at will. I did notice that they become better with destructive retribution so I am capping the amount of zombies out at once and nerfing the duration.
Horde Perfection: Zombies and skeletons stop being as effective around this level. However, I overdid this a bit. I am going to reduce the bonuses.
Improved Dread Army: This one might be a bit overpowered. Corpse Creature is a template from BOVD, I will mention that. The Duration on this one is fine. I think I will limit it so that only one corpse creature can be active at a time.
Embodiment of Death: The bonuses are the same type as what you would get when you gain a specific template. Though on second thought I made this waaaay more convoluted than I needed to. Changed it so that the Shade Channeler becomes a Lich upon reaching level 20 or a template he can animate with animate custom horde.
Improved Spirit Capacity: This should be fine now. Its nothing more than a scaling extra slot feat. (20 Spirit Points = 1 9th level spell and 1 1st at 20)
Defensive line should be horde I agree.
Pawn Shield should be fine lasting only 1 round. Undead can soak up a LOT of damage so I don't want to make it last for too long. Its also a move action so the Shade Channeler can do other things that round. I will work on something for touch attacks though. I forgot about them.
Explosive Retribution: It does have a time limit, 1 round. I guess I didn't make it clear I will improve it's clarity.
Disabling Strike: I was supposed to change that. Its supposed to be (10+Bab+Shade Channeler's Charisma Modifier). I think I might change that to 1/2 the Shade channeler's HD too.
Distracting Strike: Will add the must be threatened part.
Crippling Strike: Is supposed to be a commander tactic. I think its fine for a single strike every 5 rounds.
Swarming Assualt/Volley: Assuming 5 undead attack a subject. First one gets +0, Second gets +1, Third gets +2, Fourth gets +3, Fifth gets +4. I know it seems weird when looking at it in Real Time but isn't that how it normally happens in D&D combat?
Eternal Undead I figured was fine since it only applies to zombies and skeletons and most of the time they will not even be useful within the same encounter. I am going to add a clause that killing them with good aligned or holy weapons will permanently destroy them though.
Profane Reflexes: Will fix that thank you.
Perfect Teleporting Boon: Yes I think a move of standard action would be better. I think I forgot how soon you can get it.
Mage Slaying: Ya I agree. Do you have any good idea for another mage slaying boon? I couldn't think of anything else. Will remove this one till I get a better idea.
Profane Size: I will look at it again. I think I might of just kept adding to that one without paying attention to what it already had.
Ranged: Hm, well I always though longbows and crossbows had an initial range and then a range increment. Learn something new everyday. I will edit those.
All in all thank you for the very indepth review. It helped greatly