Sure, I believe it is often true that having a team of creative minds can lead to better results than one artist working alone. However, when you open it up to Design by Forums, especially Design by Very Large Forums, as Epic is doing with UT4, it can often lead to "meh", instead of "F'in Kickass!"
A good example of this can be seen here: The opening post picture from an oviously extremely talented artist;

Now that, is an insprining piece of artwork. Clearly a Flak Cannon, no doubt about it. Of course it's not finished, and I'll admit, it could be improved with some tweaks, adjustments, and so forth. But when you go page after page after page of more and more opinions later, it's kinda sad to see where it's ended up. The very clear badass-ery has been removed, and -while still a Very Impressive piece of modeling work, it has ended up being much less it could or should have been.
One pic posted by a forum member I think makes my point the best:

See what I mean? Is it a flak cannon? Is it yet another rocket launcher?
Ever noticed how cars (at least American cars forty or fifty years ago were unique and had way cool designs separating them all, yet nowadays they mostly pretty much all look alike? Sorta - yeah, it's nice, but 'meh'.
Just a shame is all.