Interesting. I haven't read much fanfic. Though I have to admit, the mind meld thing does sound kind of hot. ^_^
The thing I probably see most often, though, when fan fiction authors fantasize about Spock, is the desire to soothe his loneliness and to diminish his alienation by accepting him in a way that this child of two worlds isn't accepted on Vulcan and rarely finds even on the Enterprise. They want to assure him that he's perfect exactly as he is, that he doesn't need to be more Vulcan OR more human, that both T'Pau and McCoy are wrong, and he need make no changes in himself. People want to take care of Spock, want to give him a home where he's fully accepted exactly as he is.
Yes, this. Well said. I feel like a lot of the characters don't seem to appreciate him as much as they should. Now, if I was on the ship, I'd appreciate him plenty. ^_^