Depends on your playing style imo. I went Alteration, because I use charm alot. Buffing alot. And for CC, I use root(lvl4) when possible (And your group knows how to react to that
[You must be logged in to view images. Log in or Register.] ) as its fast to cast and costs nothing. (All alteration skills)
Personally I think specialization in conjuration is kinda of a waste - unless you really love to mez and basically do nothing else in a group.
But like I said - depends on how you play.