I've had a DFGT for nearly a year now and obviously tried my personal settings from F1 2010 first off, and I have to say that I found F1 2011 un-drivable. However, having read many of the DFGT posts on this forum prior to buying the game, I was kinda prepared for that as many had said they had suffered from similar difficulties.
The important thing to understand, is that F1 2011, is a totally different animal from F1 2010. I have spent all evening tinkering with the games wheel settings and also the settings in the Logitech profiler and have now on my way to having a descent set-up (I'm not quite there yet but its miles better than it was). But my settings bear no resemblance to my F12010 settings.
Firstly, it is vital to sort out the settings in the Logitech profiler first as these form the foundation of the settings for the wheel in game. I would agree that wacking it up to 100 or 150% in the Logitech profiler in F12011 is not the way to go, as makes the wheel feel like you are wrestling a dinner plate from the hands of and epileptic orang-utan.
Personally I've always found this degree of feedback counter-productive as you can't feel the subtle nuances of the track that allow you to correct a spin or lift the throttle when you have attacked a corner too fast. It would also stand to reason that too much input would potentially shorten the useful lifespan of the wheel too. However, each-to-their-own.
I'm still tinkering with my settings so I don't want to jump the gun, but I'll be happy to post them here once I feel I’ve got a decent balance.
I think its important to try and hang on in there, as I don't belive the games broken.... just different!