Yep, I saw that discussion with Dennis, one of the reasons I posted this link here, I thought it would be helpful to illustrate the point with a working example, since he's been crusading for Unity fairly strongly.
Also posted my thoughts on Google-Unity integration on that blog post. Dennis is marvelously over-enthusiastic, it's not because Google thinks Unity is the bestest 3D engine ever, it's to help them compete with Apple in the smartphone market, a space where Unity is about your best option, IMO. That's the same reason Ossian is using Unity for their iPhone RPG.
I'd hoped I was wrong, that the engine would just be SO well made that I'd never regret lack of source access, but that's not realistic. Theorycrafting about game dev isn't the same as getting your hands dirty developing something, it's only once you start working with it that you hit these walls. It's worth mentioning that now, about a week later, my threads asking for help in the forums remain unanswered, off the main pages and out of sight. Admittedly, maybe I'd have gotten some help over time if I'd tried submitting a bug report via the editor, but it's a good example of the kind of experience you'd have, having to wait for help to fix bugs in your own project.