so most people agree that dual casting 100 percent stagger is a little OP when u can just spam your spells every half second

however i certainly think it needs to be consistent as a battle tactic: timing a spell to interupt the strong attack of a deadly 2 hand weilder, or a leaping sabre cat.

the solution, as i see it, is to adjust the effect of a dual casted spell's stagger, so that it really only takes effect if the spell was held for a certain amount of time, obviously waiting for the right moment, rather than just spamming a barrage of spells that also HAPPEN to stagger the opponent everytime.

i'm not too experienced with "accum. magnitude" archetype used for wards, but would a stagger effect with that archetype increase in strength as the spell is charged and held? or is there a better way to achieve this effect?

http://www.gamesas.com/topic/1504523-building-a-continuous-activator/

The thread above is about a similar thing (holding a button for increased effect), just with activators instead of magic. That should solve half your issue anyway.