the main and best reason to level a wizard is so you can easily get to raid targets and get on the dkp logs without having to do much and you have the most plausible excuse for adding yourself to raids without actually being there

Being able to use the 2k damage bane nukes on belly caster raid mobs from max range is also fun . Also remember the best gear a wiz can get is more levels. It helps with the resist rates. So technically any wiz who isn't 60 is just gimping themselves in that department.