I think all builds need to have good damage, but some secondary trait is what will define them. What's the point of good defense if you lose because you have no offense? Anyways, characters that can't kill things on their own won't be fun for most people, so even if you disagree with the beneath suggestions, keep the fun factor in mind if nothing else.
Anyways,
TANK: High damage, poor range, high survivability.
This is logical because his defense makes up for bad range, and he can really dish it out once he gets to you.
INVENTOR (I vote for calling him Scientist): High damage, good range, poor survivability.
This is logical because his range will give him a chance to deal damage before his poor defense factors in too much.
ENGINEER: High damage, average range and survivability.
This is logical because he needs minions and excellent micromanagement to deal damage, so he isn't horribly punished in the range or defense department. However, his reliance on minions and good micromanagement put a limitation on his damage, so it isn't out of line with the rest of his stats.