I would say a supporter school like life. I find it fun healing people and every battle is always different, depending on how often you need to heal, whereas an attack school like storm just has to blade and attack repeatedly. Life gets a lot of unique spells like guidance, triage, absorb and lots of healing that you can use to support.
This post isn't about which school is the best for what it can or can't do, it's about which school makes W101 the most enjoyable to play.
I only have two wizards. Life and Fire. I have a ton of fun with both of them. I have started and deleted storm six times already because I was bored with it. Ice and balance was way to frustrating. Death and Myth, in my opinion, where just bleh.
I've been playing the game for many years. And after starting and deleting a bunch of wizards in addition to storm, I would have to answer your question with Life and Fire. I would go into a list as to why, but you said you didn't want that.