I hate to be contrary Fyrcyning but I beg to disagree.
I think many people like myself dislike Claremont so much for the exact same reasons you seem to admire him.
Once he started to feel his oats, his work became excessive and he started to write in a particular Claremont shorthand, which I found irritating in the extreme. All the "body & soul" BS and "mumpy, comfy, mumble, don't wanna get out of bed, I'm such a normal teenager" cr*p.
His characterizations became over indulgent and excessively emotive. Rather than being profound or introspective, they were facile and histrionic. Only a teenager could find anything "deep and meaningful" in the tortuous soul-searching and adolescent angst.
And his plotting, which I thought was one of his best attributes originally, became convoluted and incohesive. The X-men seemed to stumble from one interminable, illogical plot-line into another without any closure or satisfactory conclusion.
I felt that it wasn't until Jim Lee joined the team, that the mag actually became readable again.
One man's poison, right?

I also hated Claremont's ExCalibur, which I felt was ill-conceived. The team's composition seemed miscast to me and the contrived and unsuccesfull humour was a blatant attempt to jump on the Giffen/DeMatteis JLA. I feel, Alan Davis' solo efforts later on were much more enjoyable.

Besides that, Claremont's Dr. Strange was one of the least inspired runs in vol. 2. In fact, to be quite honest, I can't remember a singly storyline. All I remember is being bored and disliking Claremont's ham-fisted sensitivity, which he attempted to transplant to the mag.

I think one of the reasons many people seem so vehement about CC is that he became such a disappointment after making such a promising start.