Unity is everything GNOME Do is/was, but now with the possibility to extend even further into things like the new HUD

I never got the hang of Do, either. In order to do things with do, you have to learn its vocabulary. Whenever there was something I didn't know how to do with do (or it didn't have a certain plugin), the old way of doing it was still there. This made me reluctant to ever press the button that triggers it. Maybe I'm bad for not investing time into making it work better, perhaps desktop environments are not being treated fairly in this regard. To clarify, maybe it's hard to unlearn the ways of interfaces which came before. I was taught how to browse the web with Netscape and today I'm still bitter about certain changes in Firefox (I know there's seamonkey but it's a second-class citizen nowadays). This doesn't hold true for all user interfaces, but I'm not sure if age plays a significant part (as in, learn UI X before age Y => forever stuck with the concepts of X), prolonged use or a combination of either along with not having any alternatives (thus, not building the required mental abstraction layer to differentiate the underpinnings of various UI concepts). I have only myself to sample and given that people are using user unfriendly (or even hostile) window managers such as evilwm, fluxbox and xmonad, there have to be wildly different "mental operating systems" in any representative sample group.

Gnome usually worked well despite this psychological hellhole, I could introduce people to it and it generally wasn't met with contempt. They knew their users so well that I, for one, was shocked and baffled when at the first command I entered in the preferences of the panel applet Fish, it berated me for trying to make it useful (there's only 1 command which does that).

Most of the commonly used applications already have the most obvious keywords provided for them.

I see, that's great. Sadly this hasn't worked for me, but I'll keep this in mind whenever I'm searching in Unity and something is missing. I hope seeing how it works hasn't skewed the way I use it too much.

app developers can just provide relevant keywords for their app in the DE file they ship

Yes, I hope package maintainers will do this too. This can be useful for a11y and other desktop environments, nice.

I get the feeling from your complaints that you checked out Unity briefly early in its lifecycle and haven't checked back in on it lately.

This is false. Although I have tried Unity in each Ubuntu release starting from 10.10, I've tried hard to work with it (instead of replacing it outright) in 12.04 over the course of months. I turned to Google just to figure out where my applications are for starters, instead of flipping tables. What recently drove me away is the instability, not the glaring usability quirks. At some point, compiz flat out refused to start but compiz 2d still worked (for a while). Compiz stability is very hard to fix as it can even depend on obscure GPU bugs only found in serial number x through y of model z manufactured by {.

However, I did manage to find one improvement over gnome-panel: it's easy to use the keyboard to navigate panel applets/indicators. Just by pressing e.g. Alt+F, you can move (using the arrow keys) all the way to the power button. A lack of pointer input always renders gnome-panel useless.