There is much more to a processor than the pure clock speed. One of these other criteria is the core that it is built upon, and this is where the Backflip fails for receiving the full version of Flash. If you have any experience with desktop computers, then you might know that an AMD processor running at 2.4Ghz is on par with an Intel processor running at 2.8Ghz or more, and that can be directly attributed to differences in the design of the cores used.
Now, as far as Flash Lite, the phone is more than capable of supporting this technology, but Motorola simply decided to omit it. If someone puts a lot of effort into it then they could probably port it over to the Backflip from another device, but from what I've seen that is apparently a difficult task, as there are a ton of dependencies, so that'll likely never happen.
When it comes to Live Wallpapers, remember that Motorola has different objectives than the hacker community who puts out roms. Motorola has to guarantee speed and stability otherwise they will get a ton of support requests or returns, whereas anyone who installs a rom knows that there very well could be a few kinks. If you want LWPs, install a rom. Simple enough to do.
Oh, and just so you know, Preclair never included Flash Lite.