I dislike almost all of the episodic women he was with, mostly because he was out of character for some reason when interested in them (spores, regression due to going back in time, etc). I understand the necessity of some kind of catalyst to temporarily modify his behavior, and it's fun to watch, but it does little for long-term interest. Also, they seemed rather bland as characters (I'm thinking specifically of Droxine, Zarabeth, and Leila). All blonde and soft-focused and smiling like lovesick puppies. I don't mind sweet, innocent characters, but come on, girls. You have to work harder than that if you want to keep a Vulcan after he's come down from outside influence.
Yup, so true!
FYI, Spock gets much higher quality nookie in the books.
I always thought S/U would've been a great development in TOS, but Paramount was much too timid for that - heck, they had a hemorhage over the K/U kiss. That, BTW, was originally to be a S/U smooch.