Oy, voda, I had an idea that I wanted to propose to you. Since:
1.You introduced a few feats that represent martial arts skills and
2.You restricted race choice to human becaue of the setting.
I was thiking that it might be fun to introduce feats, flavored as martial arts styles, that mimic race features or feats. The limit would be that you can only take these feats in a "style chain" (so only from one race). It'd help differentiate the all-human group, too, without interefering with the mental image.
For example: "Style of the mountain warrior" could give access to the dwarves' second wind as a minor action; "Style of the wild wind" the elven reroll feature; "Style of the inner dragon" could grant access to the dragonborns' breath, etc.
Granted, there might be some problem in balance, but I think it'd be both fun mechanically and flavorful if done right. What do you think about it?