It's success is based (or should be) on the casters lvl vs the targets lvl. It's not the duration of it that's the problem here, it's the dodgy PvP. The fact you can hit people on the run here coupled with being cursed makes it appear alot worse than it is. Did a test the other day, on a warrior with 0 a.speed and got someone to just run around me on the spot and i'd hold shift whenever they got near. Hit them pretty much every time, which shouldn't be possible. On most other servers you can't hit a running target (unless you're alot faster than them and even then it's not overly common). Also on most other servers even when you are cursed, you can still avoid alot of melee hits or avoid single target spells if you begin to run while cursed. That's impossible here due to the sluggish movement/pvp.