To address your points:
- Lion is very fast with a SSD, but definitely slower than 10.6 with a regular hard disk. Hence the difference in perception between various people.
- The whole-screen app stuff is a good idea, but the implementation sucks on multiple monitors, which many geeks use (the problem is: when you go full screen on one monitor, the other no longer shows anything by gray linen)
- Many features were removed for what seems to be no good reason, e.g. RSS feeds.
- Some iPad-like behaviors make little sense on a desktop, e.g. automatically closing Safari if idle for a while. It takes several seconds to open a web link just because it has to relaunch the application.
- Annoying for my company, Taodyne (3D presentations): stereoscopy used to be perfectly stable on 10.6, unstable since 10.7, to the point of causing kernel panics or system freezes regularly.
- Memory management has been a weak point since Rhapsody. In Rhapsody, you could crash the system simply by zooming in Preview. Today, you can still halt your top-of-the-line system to a crawl simply by running a process that eats all available memory. I'd much rather have an easy quota system where I can say "unless otherwise specified, no app can take more than 1/4th of available RAM". Or a paging system that makes smarter decisions and keeps the "interactive" stuff resident enough that I can still kill the offending process.
- Tons of annoying little bugs at the lowest levels, and you really wonder what was broken there that they needed to fix. Like the mouse cursor that sometimes disappears. Or the keyboard that sometimes forgets half the keys you type. Or Safari that stops refreshing part of the screen. Or moving a window across monitors that now causes the window and background icons to blink. And so on. Lion does not feel as polished as Snow Leopard.
Overall, I still like Apple products, but I definitely see them losing their edge on the software quality front. I think that Maps on iOS is just the most glaring example, but it's not the only one.