If it wasn't soooo frustratingly difficult...
The change between "Medium" and "Full" sim level is huge in terms of handling, and they really could have included separate assist options. On Medium I find no challenge even with hardest AI, and on Full I usually fly out after three or four laps due to some minor mistake. Problem to me really is that the pinpoint accurate control needed for full sim, even on a good gamepad, is not always easy to manage.
Supposedly 2011's "Full" is somewhere between 2010 Med and Full, so please let me know what you find Plainsman. I love the game to bits but after two or three evenings in a row I usually quit in frustration.
Amazon says I should get the package today, so look for a post later tonight, EST, if it arrives. I have the same problem with SBK X. Once I figured out the gamepad (I hate gamepads, which is why I never play consoles) I easily won a race on Simulation-medium. And, like your experience, Simulation-full is extremely difficult for me. The slightest contact with another bike, even a tire, and my face is all over the asphalt. But I blame the lack of an ideal controller for a Superbike sim rather than the difficulty level. I just hope the rain effects in 2011 are as good as 2009's. Why they toned down the rain effects in SBK X is a head scratcher. Rain in SBK 09 was as good as in Rise of Flight--spectacular for a bike sim.