The transition to Vista isn't at all what it was with XP...
You're comparing the migration from Win98 (largely built on DOS) to Windows NT5, in the case of XP... The result was miserable upgrades for many users not only in hardware incompatibilities (drivers were vastly different), but software problems as well. It's apples to oranges. Vista is just an upgrade to the existing platfrom, so you can't expect the magnitude of problems we witnessed of the change from 98/Me to XP. Most of the problems stem from the 64-bit revolution which require new drivers.
That being said, I completely agree with you on the transition from XP to Vista-- to an extent. There's too many functions that were changed from XP, to be buried underneath other submenus in the control panel. Often there's redundancy, where you can find the same function under several different menus. Things were renamed when they shouldn't have been, only to access the same functions as in XP. Several different menus have been recreated and/or renamed in the control panel which leaves XP users confused. Networking especially.
The hardware requirements leave me completely baffled... I consider myself a power user, but I wasn't prepared to toss another 200$ in the can for an extra 2GB of RAM to run Vista. I started with 1GB of PC2-6400 on a top-notch system (see sig) only to be surprised that Vista and the core programs I run (AIM, AnyDVD, ATI drivers, Win Defender, Symantec AV, etc) eat up the entire 1GB from the get-go.
As a power user, I need at least some headroom in terms of RAM. I quickly found that running any modern game such as BF2, BF2142, etc, with 2GB was acceptable --- until you had to switch to the desktop -- That was a nearly 2-5 minute process as Windows paged to the hard drive. So 3GB it was.
I actually contemplated installing Vista on my Laptop which is a P3-1.2ghz w/ 768mb of RAM. After seeing it run on my desktop, no way would I consider it.. How Microsoft can vouch for compatibility on a 512mb RAM system is beyond me, but I imagine there's lots of suckers out there upgrading only to purchase a new computer weeks later.