I agree that Unity is to blame.
I've used several distros and moved back to Debian for stability, personally, but always installed Ubuntu to my friend's with chronic computer virus problems. After Unity's release I was lost though. I'll admit that after using it for a few days (new work computer, needed hardware support ASAP) there were a few things that do work a bit better, but it's far to drastic of a shift. I ended up with Debian, backports, manual firmware installs, and a working stable *familiar* system.
What Ubuntu was doing for Linux popularity was great, and it's a shame to see them take such a dive. Ubuntu was good because it was what it was. Trying to do something so drastically different will alienate people, and I'd bet there are other techs like me out there that just don't have the time or drive to learn another UI when we have Windoze to deal with doing that already!
Personally I would like to see an OPTIONAL Unity install. I know it might be hard to fit on a single CD, but if during installation (or a separate download) I could have my pick of Unity or Gnome, I'd be happy. But that's a lot to maintain...And rolling back to Gnome, which I tried, wasn't as trivial as it seemed. It look me less time to get Squeeze working on brand new hardware I'd never worked on than it did to fail rolling back to Gnome. To me, it just wasn't worth the effort to make Ubuntu work how I wanted it to. I chose Ubuntu because I don't need to do that.