A few things that it can improve the game.

New Feats.
The list of feats, its not bad at all, but it can be better, the official list its much more longer than that, and i dont think it has a big problem if the devs implements a few feats.

Add ECL in Mid Game.
In pnp you allways can get in middle game something that can "change" and improve your character. The simple example it's "A lycan bites you, now you are a werewolf, you have a regeneration rate 1/R, dmg reduction 2/silver, when the moon its full you can change to a wolf. get a +2 to str and +2 con, a -2 wis -2 int -2 cha when transformed
But now you need more experience to lvl up.