Did I make a mistake by choosing to play wizard?

[Velerin]

Wizard was my main on live and was good times, fun for maximizing dps on raid bosses, etc. But in this era in a typical grind group of tank and spank, you are a burden and any other class will probably outdps you over time as well as do other things/buff.
I haven't had anyone confirm here but concussion is actually a great spell. On live, since the way the code worked on spells ( a resisted spell = same agro as a hit spell) a resisted concussion still lowered agro. I was usually always top dps on raid mobs as my wizard (nuke, clicky, nuke, clicky, concussion, etc etc.

On that note if anyone with a wiz could test this it would be awesome to find out for sure:

Need 1 mob with high MR but doesn't hit too crazy hard. Have tank pull it (but not do anything else) so he has agro. Cast flux staff slowly just until you pull agro. Then cast resisted concussion and if mob turns back to tank it does work on resist.

Any ideas on what mob will work for this? Black Dire? anything else that will resist but doesn't hit hard?