So what change to evac would make everybody happy? Make it uninterruptable for all classes that have it? Make it more interruptable on a scout? Seriously, what change? I mean, my ideal suggestion would be to make castable on the run for everybody. Really, if you think about it, it's the most important thing on somebody's mind when about to get whacked, the whole Bugs Bunny "GET ME OUTTA HEEEERE!" thing. But then I'd wager that every class that doesn't get an evac would probably just get more upset.
Know what I'd love to see, actually? A Q/FP faction item (something with a cost along the lines of a pumice stone) that allows the user (regardless of class) to sacrifice themself so that the group, excluding the user, could evac. That is assuming the user hadn't done anything that would normally prevent them from evaccing. Ensuring that the user dies (root them in place for 30 seconds, heheheh, just to screw with anyone planning on popping that, then Manashield) would keep it from being abused. Call it an "Amulet of Martyrdom", or somesuch. And get rid of perma-immunity upon evaccing, make it a minute, max.
Any thoughts one way or another?