If Humans are the strongest race (Human adaptability) why do they make the worst melee characters?

Dwarves have axe enhancements and +2 Con
WF have powerattack and +2 Con
Elves get LS/Rapier enhancements
Halflings get sneakattack damage and +1 ac

A being able to get +1 str only gives an extra 0-1 damage.

Dont get me wrong, i play multiple humans, i like the race, and they make great sorcs, wizards and clerics.

More useful feats would definatly help humans out a bit, but i would rather see work done on human enhancements.

A couple ideas:
-Allow human vesitility to count for other PrE requirements (for example:damage boost for assassin or attack boost requirement for Kensai)
-Human Power attack (requires HA:strength). If a human is stronger the a WF why not have this?
-Bastard Sword/Greatsword attack/damage enhancement line. Hey, even with this people would still use Khopesh and Greataxes