You had way more issues than that on launch, performance of 3d games sucked compared to XP with the same hardware (I remember at least a 30% decrease of FPS) and usb file transfers were so borked you probably had half of the speed of XP transfering on a usb key (which was the primary method of transfering files at the time).

The UAC wasn't even the main problem, the overall performance of Vista was, everything was so much slower.