Good luck killing a bubbled Wiz who can deal 400 damage each FF. I hit them for around 40 per swing, so to kill the wiz with shield up, I would need to hit them 6 times? Assuming they don't sun / pot. lol.
Koriban is derailing the thread again, but without going too off topic..
I'm a lv50 wiz and hit an average of 200-250 with full mc kit, its only the fully top end kit/lv3 MB that can hit 400. Also, no one seems to appreciate that the cast delay for FF (an other spells) is huge compared to the number of hits an aspeed warr or sin can put in during the same time period. It can easily be out sunned (even with the 1 second delay), unless you have 2 to 3 wiz around you.
With or without MS I cannot simply stand and FF a warrior or sin. It's more like FF, run like crazy, FF, run like crazy etc. If they land a hit or two it's 50/50 that I'll be able to sun/rt/tt quick enough (maybe I'm crap but most wizzies die pretty frequently compared to other classes).
To sum up shield in pvp;
Depress (and similarly kitted warrs) kills me in 1-2 TDB and thats if im lucky enough to have shield up.
Sins, yeh maybe 4-6 hits with shield, which seems about right to me.
Archers have piercing shot which ignores the shield anyway and static shot which flinches like hell.
I admit Taos struggle solo and have to rely on curse/deva flinch & other classes to put people down in pvp, they just cant deal the damage quick enough.