That seems to be the norm. If you spec yourself properly you can get into some crazy imbalance issues.
Of course, it varies by enemy resistance. For normal creeps, I'd say as a magic user with all everything maxed for offense and active skills on, I can hit for almost 1.5k per magic missile so damage is around 10.5k. Some bosses go down real easy-- a single volley. But the final boss seems to have high magic resist. I'm not sure what the max on crit is, because with magic getting seven straight crits doesn't happen too often. I know magic blast is supposed to have better damage but I'm not sure I ever see a proper number appear when I use magic blast.
