The simple fact is,, UAC can and does prevent programs from running that require Admin rights.
Plain and simple,, stupid idea or not, it's a fact. You have said it yourself that, that is what it does.
So, to get back on full topic of,,,,
Should anyone turn off UAC or not?
As it works the way it is intended and it does work.
The answer is No, you should not.
What one does in reality is their own business. And not my problem, till they start complaining about getting infected or having other issues and you find out that it might have been preventable, but they disabled a tool that could have saved them the grief in the long run. My answer will always be,, plain and simple, because it does what it is supposed to do,, run as standard user with UAC enabled. Is it the best perfect all around wonderful god like utility that we hope and wish it would be? No. But, it's not a useless tool either as long as people pay attention to why it is popping.
This is a controversy that will go down in the annals of all that is MS, just as activating XP did back in the day, just as Run with no page file or what, still is today (even though it's has been proven time and again that it is best to run with MS recommended page file sizes regardless of how much ram you have installed).
So, why do I say run with UAC is my standard answer?
Because, I know people, and the largest majority of people asking this question, do not know what they are really doing, are not really all that safe of surfers or stewards of their own security. I also am not here to tell anyone how to run their own system or protect them from themselves. That's not my intention, nor my job, and frankly speaking, I don't want anyone forcing it on me. But, we also all (as techs, or more experienced users) provide the (not sure how to put this) ,, best answers, not always as we ourselves run our system but how a system is intended to run, to the best of our knowledge. Giving security advice that works for us, is not something that always works for everyone else. Spitting out some of the answers I have seen in this thread, many are well, irresponsible. Bad Advice.
Putting even more simply, and which may become my standard answer to this particular question is...
Q. Should one turn off UAC or not?
A. If you have to ask that question, then No, you Should not turn off UAC.
Actually, I'll make that part of my sig.