I'm looking at some of the guilds that have been downing bosses on my server and their ilevels are so high.
Killing Siegecrafter with 582ilevel and Garrosh with 584 ilevel.
Are these fights even comparable to what they were when earlier guilds killed them? The output and health differences seem immense and the fights seem to be completely different. You no longer have to play at a extremely high level and do everything right. You can bring more healers, not worry about optimizing dps etc.
For me it just wouldn't feel like a big accomplishment. Especially if you're a guild that has raided from the very first week. It's more like you bashed your head against bosses till they fell over as opposed to winning through skill.