Haste, Rage, Displacement, etc. should all be doubled duration

[Maegin]

I would keep extend on bards and wizards and thats it. As a bard extend is their pretty much to let you buff less often and be in the mix more often. Wizards have the feats with the free metamagics, and as a PM I would use extend for the aura alone.

The feat no longer has enough value to keep on a class that does not get bonus feats if it does effect offensive spells. If it was not possible to get any of these buffs from outside sources I might have a different opinion, but when I play a melee I carry potions, wands, scrolls, clickies whatever it takes to be self sufficient. Their are so many ways to get buffs that I don't consider it the casters job to keep me buffed.

I do agree with Matt that if extend is losing its use on offensive spells, then just remove the feat and front load the duration of all buffs that are not 1 min per caster level.

^ This. +1