[PvK]

I think it's kind of neat with the light spell, but with combat spells it can further unbalance the system, as the examples mentioned show. There should be a way to specify which spells stack and which don't, and the ones that become overly powerful or make high-level skills pointless should not stack.

As for duration, I agree it is pretty short for many spells, particularly for buffs, to the point of making them more fiddly than they are usually worth, especially if you aren't playing with the speed turned way down.

PvK