what's so wrong with that? I need to run Morrowind as an admin or else MGE will not work. I don't run Oblivion like that though.
It's to do with security. Pointedly? The lack of it, in your case.
You don't need to take my (or another forum member's) word for it though. If you read up on this stuff, you'll discover this is by far the best -
and easiest! - way to go about things, with Oblivion (and many other games) with Vista or Win7.
It's your choice, of course, but security-wise, you'd be better off changing your approach. Same reasoning behind Ubuntu's sudo system, etc. You
can just run Linux as root all the time, but... it's not advisable, let's just say.