No pokemount. Ever. In fact, Paladin is a PrC, not a base class.
No oriental classes, including the monk.
No base class has an alignment restriction. That's part of what makes them a base class, not a PrC.
Cleric has been replaced with Hong's Priest class. Either way, there's no such thing as a godless priest/cleric. Look up "divine" in the dictionary. Anyone trying to apply the word to something not involving a god (or something "really nice", to be pedantic) is not speaking English. "Divine magic", by definition, is magic from a deity.
No substitution levels. Dumb concept. Races as classes are one of the things I least liked about OD&D. Bringing it back, even in part, is not a good thing.
Bows and crossbows flipped their crit range. The research I've done indicates that bows are more accurate when fired by a proficient user, but crossbows have more power.
No sorcerer. Not because I dislike the class, but because it's a bit pointless when using the spell-point system from UA.
No halflings. Don't much like gnomes, either, but I wanted to allow some sort of size small PC race. If I hadn't already had a PC gnome (a Spirit Shaman, either -- talk about no loving from the DM), all gnomes would have quietly morphed into whisper gnomes.