If you see a 6/6 wizard/sorcerer who wants to join your group, let him join. If you run a quest with him and he's fun to group with, I guess he doesn't have a horrible build. If he dies every four seconds while screaming how awesome he is, then don't group with him again.
There isn't one "right" way to build anything. There isn't even two. If your own character is too weak to survive with anything less than a full group of uber-geared min-maxers's with multiple past lives, then it's time to TR and roll a better character yourself.