not sure if this has been mentioned yet, but I was just thinking about some 'AOE-changes' that happened in the last couple of operations (raids) in SW:TOR

basically someone gets 'tagged' with an AOE-effect, and then they have to 'place' it either in a specific spot - or generally away from the group or boss (sometimes ON the boss). once the effect is placed, the player still has a couple of seconds to actually move out of it.

some variation of this is that one player gets tagged with the effect anyway, will get a HUGE hit (not deadly if fully healed off), so everyone else basically has to move away from them or else the healer won't be able to topple off the entire group for the next big hit.

it would still give people enough time to MOVE, but it would still be difficult enough to provide a challenge.

or something else from that game, the 'barrage' (found in 2 operations so far)
basically it's a little droidsomething that will follow one person and leave behind a trail that damages, so this means a) the person with the barrage has to move away from the group (preferably not by running through them) and b) the group has to be aware where the person with the barrage is

I love these mechanics. SE has copied so much, they should copy those! (no clue if such mechanics already exist in other games. they probably do :P)