
Curly, don't make me cry... Science Fiction can be both awe inspiring and humorous. I think the only science fiction author I've ever read that could be considered pedantic is Jules Verne, and when reading his work you have to realize that the reason he was spending so much time with detail was because he was imagining things that had never been imagined before.
I cannot even comprehend why anyone would say Science Fiction is unimaginative. It is one of the most imaginative genres out there, because the purpose behind science fiction is to write about things that are not possible yet. It was no coincidence that the first interracial kiss on TV was on a science fiction show (Star Trek)... in what other genre can the controversial be something that is not only imagined, but accepted as a potential reality?
As for whimsy, there are many science fiction authors that convey a sense of whimsy! Isaac Asimov, Artur C. Clarke, Orson Scott Card, Dan Simmons, Connie Willis, John Scalzi, and Alistair Reynolds are all contenders. And new science fiction writers keep coming; personally I find that new releases in other genres are often stale, while there's always something juicy in the sci fi section.
To answer the OP, I haven't read foundation yet, because for some reason I can never find the books in order when I look for them. I have, however, read his "I, Robot" short story collection, which was excellent. I'll have to seek those books out again and see if I can find them in order this time.