I like 'em, and I'd like to see longer lists. Perhaps an effect for each kind of weapon would be nice.
I did a few similar things in my own rewritten fighter feats, so here's a few more suggestions on what you could add to other weapons from my list:

Battleaxes cause bleeding wounds, or you can attempt a sunder against the opponents shield or armour when you hit him with power attack.
Hand crossbows can be fired as a swift action with a -5 penalty.
Flails give free disarm attempts on a hit.
Picks and hammers are armour piercing, ignoring part of the enemy's armour bonus to AC.
Polearms with reach can be used against adjacent enemies as well.