See feedback is useless if it's not constructive. The main reason people feel that evokers suck is that they tried to level one in the leveling beta server and got wrecked in the Dragon Isles because compared to their mains, the Evoker is about 100 ilvl behind. You cannot really argue that the Evoker is not effective; their damage is very high as is their healing. They have a very strong niche in burst healing that may well make up for the reduced range they have in raids (and doesn't matter much in dungeons); your raid leader will just have to assign the Evoker intelligently.
The only concerns I've seen that are actually valid are:
a) Defensives suck. They heard that feedback and fixed that today. Everyone was reiterating that feedback (including Rage in this thread)
b) Devastation has no build variety. I don't see them fixing that before 10.1
The idea that the healing range might limit their viability for raiding is not problematic but it has not materialized in testing. Really at this point data does not support it; they have a limitation but they make up for it with exceptional performance in one of the most important niches in raid healing (frequent burst healing). It's a natural worry to have but at this point it seems the problem is PR (exacerbated by people projecting that concern which they cannot actually substantiate) which may affect the meta.