Imo, i think those buffs should last for ever, only disappear when the world ends at 2012.

Seriously? could you be more lazy?

What is the problem of casting buffs every 5 min? From all the things you could pick from the "bull s" pool, you just piked the one that had no problem at all.

Increasing the time of the buffs wouldn't bring any tactical advantage whatsoever, at the exception of adding laziness.

So, imo, no, no, and no, there is no need and it does not improve anything.