yep my MBP from last year runs on the same old C2D I had when I had a 15" unibody and a pre-unibody MBP.
But I like the battery life (or did before I 'upgraded' to Lion, which is why I switched back-- this is a Mac portable not a desk-tethered machine), the smaller factor (relative to 15" I was used to, haven't looked back honestly), and I don't game and rarely encode (mostly use the machine for photos and casual tasks) so i don't mind.
Plus SSD lets this puppy fly for daily tasks. So 'slower CPU' doesn't bug me too much. Plus, I still think I like having the 320M over some 'Intel integrated' junk. Intel and graphics cards should not be in the same sentence.
I'd be more annoyed if I bought a top spec 15 or 17" from last year (I had the antiglare 15" i7, but returned it because it was 2 x the price of the base 13" and I didn't use the additional juice), only to have the base 2011 MBA keep up or even beat it in benchmarking! Talk about impressive!
I really don't think C2D is what makes Lion run slow. I think Lion just runs slow. Try playing with it on a 2011 13" pro at the store, the graphics are glitchy (full screen animation, it hiccuped every time).
When people say they "have no problems," I really think it's just they aren't as observant as you and I and others who are nitpicky (and are not trolls, and otherwise like Mac products). Unless they already have a shot battery that doesn't last, or never part with the AC adapter... Notwithstanding perhaps a few Mac models that Lion was probably built with in mind (ahem 2011 MBA, some desktops maybe, etc etc).
Even the home page says 'Lion: the king of desktop' (but note, not the laptop haha)