Sorry I'm taking a while to respond, been really busy lately.
The best "Leader" archetype that's still fun to play should utilize White Raven maneuvers, which is exactly what I did with the marshal. I really don't want to retread old ground with the dragon shaman, and the only other way I can think of to provide variety as well as a party support focus involves giving him spellcasting, and that's really not what I'm going for here.
On that note, I'm thinking about returning Touch of Vitality to Charisma-dependent, but powering it a little more. To do that though, I'm going to need some other things that Charisma would be good for besides just Touch of Vitality, so it doesn't become an easily dumped ability. Maybe something to do with auras or Dragon Ally?
I need playtesting to be sure, but it doesn't seem too strong compared to ToB and certainly not to casters. With skirmish, you're pretty much restricted to certain (very feat-intensive) methods of combat, like Manyshot and Bounding Assault, unless you manage to get some reliable form of swift-movement or something. The Favored Enemy bonuses generally aren't that strong except in specific instances, and the improved spellcasting progression probably just saves you money on a few extra Pearls of Power. The Bonus Feats give the biggest power boosts I think, and I'm reluctant to cut those since your combat styles are just too feat intensive.
And yeah, need a better split for humanoids. Not sure what would make sense, though.
And a lot of these are a bit of a stretch when it came to coming up with ideas, so suggestions are definitely welcome.
For Vermin, I wanted these to represent you using your learning of these creatures to expand into more generalized combat. So if you learn to fight Vermin very well, you should be able to generalize those methods for other smaller creatures. Vermin's abilities are usually more powerful than others because Vermin are so rarely encountered, so I need to give some incentive to make it a viable option.
As for balance, there are very very few high level creatures smaller than Small. And even if there are, they gain progressively higher attack bonuses for their size. A Fine creature gets +8 to attack; a Medium ranger gets +8 natural armor AC in response, just canceling out the bonus. It's not very high and again, it is a level 20 ability for a rarely seen creature type.
Would it help if I add fluff explanations before each ability? I didn't do it before because I thought it would just make that section longer and more involved than it already is, but I can do that if too many of them defy explanation. And I definitely need some help with new ideas to replace some of the sketchier abilities, since I want to avoid plain +stat type abilities.