Akashics, champions, unfettered, warmains, and totem warriors give up fairly little by taking some racial levels. A giant 3/warmain 16 is a pretty devastating combat machine. Size large, +4 Strength, +2 Constitution, wielding a Gargantuan weapon......or two Huge weapons if they spend a few feats on being good with Two-Weapon Fighting..... They miss out on just one or two warmain bonus feats plus Weapon Mastery (just means 2 less damage per attack), and their Base Attack Bonus will be one point lower than a pure warmain, but the Str, Con, and weapon size boosts more than make up for it......
Granted, racial levels in AU don't mesh well with classes that are predominantly magic-users (and it puts mage blades, runethanes, and witches even further behind in magical ability). But still usually good for characters that emphasize combat power, skills, or whatnot.
I really would've liked to see Verrik racial levels actually fixed to be worth something, but alas.... Verrik still have no way of being really effective at anything but the witch and greenbond, and even then they only suffer weakness if they take racial levels. Though I'm glad Arcana Unearthed makes Charisma much less of a dump stat, it's still annoying that Verrik are mediocre or inferior if they take most classes besides witch and greenbond (as those are the only classes that get any real use out of Wisdom, and too many classes rely on Charisma or Intelligence instead). Verrik racial levels are only possibly decent for akashics (since the 3rd Verrik racial level can boost either Int or Wis). I really wanted to like Verriks for their minute psionic magic affinity, but it turns out that it blows, and half the spells in AU that ought to be of the [psionic] descriptor instead lack it. But then, AU's races generally disappoint me with their blandness and the fact that hardly any of them are actually talented in any given field (i.e. giants are good melee types, while both faen and litorians are good archers, and mohj are good arcane casters and akashics.....but that's it. they're all generally inferior to humans for any role other than that, and the rest of the AU races are inferior to humans at pretty much everything). /rant off