As someone that play's wizard, so I may be a bit biased, I don't think it needs to be nerfed. Orb and spark bomb are tied to level. Orb needs at least lvl 3 and spark takes up 1 entire level. The thing about wizard is, we don't start off with the availability to spam out these spells. Magic darts, sure they stay on map for a while, but they are so easy to dodge. The problem comes when you let a wizard sit back and set up 10 of these things that you must dodge. Keeping in close proximity and not letting spark orbs pile up is key. And if you haven't figured this out yet, dodge rolling into a spark orb can set them off (if you time it right) for no damage. If you do it just right, you can take out a row of orbs in 1 go as well. I had someone roll and destroy 3 one time against me and I was pretty mad. I think there's a few moves that can also set them off prematurely, but I don't play enough of the other roles to know what they are.