Vista wasn’t well received more as a matter of perception than one of technology, as well as Microsoft trying too hard to accommodate manufacturers, vendors and distributors.
From a user standpoint, Vista [Aero] represented a huge cosmetic change and people, who had pretty much grown up on XP were presented with an OS that “didn’t work right” even though much of what Vista brought was more efficient and better integrated into the OS. People resist change even if it is a change for the better. Especially when it's the only OS interface many knew. There were so many people who had never touched a PC before joining the computer-using public in the XP years.
The driver issue should have been laid squarely at the feet of hardware vendors who had the time, information and responsibility to provide working drivers for their products. Unfortunately, MS had a history of allowing poorly coded drivers to have access to levels of the OS (HAL) they shouldn't have, so with XP, many vendors took shortcuts that went directly against Microsoft’s API programming recommendations. The Vista RTM enforced those recommendations and broke the crappy drivers. Vendors knew this, but I suppose they believed that MS would back down at the last minute. Kudos to MS for not backing down, and shame on MS for not enforcing those rules a long time ago.
It goes without saying that people hated UAC. But those same people are the ones that needed it most and understood it least. It’s really an instance of MS trying to protect users from themselves and users figuring out ways to be stupid and still being able to point the blame elsewhere.
The biggest blunder, IMHO was the “Vista Capable” certification. It was simply lowering the bar so vendors could move a lot of old inventory. Again, they knew Vista was coming and had plenty of time to deplete old inventory prior to the release, but people were clamoring for the ever-cheaper PC so cutting corners was a matter of course. Putting Vista on a P4 with 512MB of RAM is crazy, but they did it and pissed off a lot of users who couldn't run Aero … or run it well.