Saeviomagy
Adventurer
Which once again causes the player to cling to that type of sword in exclusion of all others.
Which they'll most likely do anyway. There are only a few weapons on the basic list that are worth using: anything else is essentially a trap that's best converted to one of the good ones OR can be made useful via feats. But once again - a PC who takes those feats will be best served sticking to weapons that let him make use of them.
The only way you're going to make the weapons system such that a PC doesn't favour one weapon over another is:
1) remove all differences between weapons (ie - you have one simple thrown/melee weapon, one simple ranged weapon and one simple melee weapon and it could be an axe, a sword or a club, do the same for martial)
2) make the differences between weapons so small that magical weapon properties drown them out (that means no +2 vs +3 weapons, probably change the rogue +1 with daggers to +1 with everything etc. High crit, versatile, thrown etc can probably stay, as can damage dice, but the high accuracy weapons will need to be changed so they matter)
3) make magical weapon properties so large that they drown out weapon properties (who cares if you're +1 to hit with your dagger when the new sword you got makes your at-will attacks into close burst 2s?)