Exactly, the people who use a Mac as a serious tool - and not just as an expensive toy - want a credible computer OS. Not a phone, not a media play-thing. You don't design a building, compose music score, or edit a feature film on something by fisher price.
And how is OS X not a "credible" computer OS ? Lack of "All Windows" expose ? Full screen apps only working on 1 monitor because they create their own space and don't share it with other apps ? What ?
Or is it that OS X is a credible computer OS, one built on top of a foundation built by some of the best minds in the industry over the last 40 years (names like Dennis Ritchie, Ken Thompson, Richard M. Stallman, Brian Kernighan Bill Joy, Kirk McKusick, Keith Bostic and many more), a foundation that has inspired many and brought us great innovations like Tim Berner Lee's little known software called WorldWideWeb, which he wrote on the NeXT computer at his desk.
No really, posts like this make me laugh. A few bits of UI candy and suddenly everything that's underneath is gone and doesn't exist. Guess what ? The UI candy is a distraction! Underneath is where the real guts are and where the real computing happens. And that is what is called OS X. Forget the Mission Control, Expose, Spaces gimmicks and forget the people who say a "professional OS should have All Windows Expose!", those are simply ignorant of what true computing is and how it is accomplished.
The fact is, my iPhone, an iPad and even an iPod Touch are all turring complete computers, running a OS (iOS) that is much more advanced than a lot of stuff we used to use on desktop computers. Sure it goes back to a single user paradigm, and tends towards the single task as well (whereas OS X is a multiuser/multitask system), but that doesn't make it any less of a full OS with proper kernel and user space seperation, hardware abstraction, systems services and a full on graphical UI package. It's also fully programmable with a free toolchain provided by the vendor to do so, which is more than I can say for some "real computer professional OSes!" (Looking at you HP... aCC really needs to cost thousands of dollars ?).
I for one am quite happy with OS X Lion, will probably be with OS X Mountain Lion. I have concerns because of Gatekeeper's current default of "App Store or signed", but that is about it, a default option that can be changed (and maybe won't even be the default after some feedback from devs to Apple). The rest is either good sense in merging protocols/accounts from iOS into OS X (I want iMessage/Facetime/Airplay on my Mac to match my iOS devices) or simply bloat that is ignorable (Twitter, Launchpad, ShareSheet, iCloud).