> as the technical users leave Gnome because it's not as useful to them anymore
I'm fairly technical and I'm not leaving Gnome. There was a time I spent hours downloading themes, sometimes building my own from them, so that I'd have the "perfect" desktop, but not anymore. The most time I lost in the last 6 months was tweaking my init.el file so my Emacs would start with everything I need to work comfortably. I also built a console font so my terminals and text editors would mitigate my 3278 nostalgia (https://github.com/rbanffy/3270font).
A theme is just a theme. We don't have to fight much over it.
API breakage, OTOH, is a problem. Anyone who develops for Gnome should have a continuous testing install somewhere running tests against the latest master branch to prevent nasty surprises down the road. Also, people who develop apps and feel Gnome is going in the wrong direction should get involved in Gnome development. App (and theme) developers are the users of Gnome's APIs much like I am a Firefox user. If it "feels wrong", I'll get in touch with the developers and try to help fixing it. Ranting is not going to help.
I left a few months ago (now I run a mixture of OS X and Linux with Openbox) and I know I'm not alone. I'm afraid that I can't post statistics - although I'd be very interested to see them, if there are any - however the general feeling I get is that a lot of users are very unhappy. Here's one high profile incident, which I'm sure you'll have seen: http://www.theregister.co.uk/2011/08/05/linus_slams_gnome_th...
I've also spoken to a few of the developers of the core Gnome applications and morale, from what I've seen, seems to be pretty low with some groups of developers simply refusing to implement changes planned by the design team. I'm very concerned about the project - I think the new vision will lose them both users and developers, at a time when they need them more than ever.
Most people I know who moved to Macs didn't do it because they felt Gnome was bad. Most of them did so because Macbooks are excellent computers and OSX is a good enough Unix they can work with.
This design-development schism seems bad indeed. Maybe Gnome lacks a decent leadership, one that lets it be Gnone rather than Windows (Mono, seriously?) or OSX. But then we'd have to know what it is to be Gnome. I kind of like Gnome Shell and Unity and lack of themes means I spend less time customizing my machine and more time working, but I'm not a typical Linux user anyway. What worries me the most is not product quality, but all this toxicity floating around.