Please correct me if Im wrong, but afaik there is no MMO currently on the market, except for AoC maybe, that got graphics that A7 cant recreate with a medium amount of work. So theres no problem with that.
Don't underestimate the core parts of those engines though, as they aren't designed for heavy duty AAA graphics, but rather smooth MMO experiences even on 5 year old PCs.
Having said that, there are a few CryEngine based MMOs coming out soon which might stir things up when it comes to the MMO graphics standard.
At least I hope so, I hate those World of Warcraft-style clones.
