The Only reason to have the UAC at the first step (the lower before total removing) being, without UAC, some desktop gadgets crash for some reason I can't and don't want to imagine
and they do it "always" at the worst moment possible.
other than this it should be totally removed indeed, it is more an annoyance and hindrance than actual security enhancement, to the point of nagging the user over if he wish to type that letter on a text file... OK, I'm exaggerating here but less than it seems.
Not being "satisfied" into nagging all the time, it will silently deny access without any warning every time that can cause harm to the user (and I mean the action of denying, not what is being denied) leading to most difficult to understand problems and issues.
One the most common and recurring issue caused by UAC is that that arises from installing on "protected folders", like the "default" C:\Program Files and ... behold in AWE... the Users folder and it's subfolders which includes the Documents folder.
It's something totally unintuitive the notion than applications should never run from the User's Documents folder and the reason is hard to understand in deep but easy on a layman level and resumes in this:
Although the user has total control on that folder... the application running from it IS NOT the user even when it inherits some the user's privileges... so the "security mechanism" will see many operations from that application as a tentative of invasion... the rest I left to imagination. This issue is aggravated if the offending operation comes from a third party like a plugin or mod or maybe a simple dll.
PS: Running from inside the Documents folder is yet worsen than from C:\Program Files... because it can hit XP users too and not only Vista or Seven users, although not so frequently or hard as in these last.