It feels a little clichéd to say it, but I do feel that Snow Leopard, outdated now as it is, was some kind of fortuitous confluence of factors that resulted in OS X being as close to perfect as it's ever been. Even putting aside the iOS-style elements being added, my experience has been that each version of OS X has been slightly worse than the last, and tends to introduce strange little anomalies and instabilities o…
I think you have rose colored glasses about Snow Leopard. It had plenty of bugs and hiccups. People deride the "iOS style" features of El Capitan but first, what specifically are you referring to besides Launcher? Do you think adding Notifications to OS X is bad? I find them extremely useful, and like the integration better than the spotty support Growler had among third party software. I never use Launcher but it's…
You're right that there's a certain amount of rose-tinting with regards to Snow Leopard. It certainly wasn't perfect, and I wouldn't really want to switch back to it; the world has moved on since then, and SL isn't really competitive as a primary OS now.
With that said, though, my use-case in OS X hasn't dramatically changed since Snow Leopard --- mostly web-browsing, some IM, using the Terminal for various tasks --- but OS X's stability has changed in that time, for the worse. Apps crash more often, the OS itself is generally less stable and prone to random freezes which require a hard-restart. Doing a fresh install didn't fix these issues, and my fianceé's MacBook has them too, which makes me think it's not just hardware issues.
I think what I'm really looking for is Snow El Capitan: a year where nothing new is added and Apple throw intense focus on fixing the various weirdnesses that are introduced during their breakneck release cycle.