Buffs that last a bit longer

[DeadRiser]

Not really.

Having to grind is like being stabbed. Just because you've been stabbed, would you mind being stabbed again any LESS?

I never felt a stabbing sensation when buffing. It's not that much of a pain to buff every 5 minutes or so. I'm with the other guy, everything is easy/simple enough.
And the deal with the 30 minute timer for Defender and whatnot, they are giving up a percent of their attack for physical/magical defense. Unless you want to give up some of your defense for others, or reduce you're magical/physical attack for others defense, I'd keep the buffs as is (just make them a little stronger as you rank up).