I want my wizard modes to be multiballs. I enjoy unlimited fast paced multiballs with tough objectives.
I also like wizards that have a tough shot that lites to start it.
On the other hand, I also enjoy wizard modes that have a series of objectives that need to be made in order in order to start with a consolation mode if you fail.
I think a good wizard mode should have a strong relationship to the conclusion of the theme, and I think that's really what make the wizard mode stand out and special compared to a normal mode.