I can see where your comming from, i myself find warriors and rogues are often a problem, warriors more so as they always try to fear bomb me right away.

Personally i think that haveing one melee class while the others are ranged will cause you more problems than you think, biggest issue will be haveing to bring your melee character into combat, you can either bring all your warlocks up close to the target your melee is dpsing or move them about so they are slightly behind, but i would think that this would leave them very exposed to other oponents.

it could work, but personally i dont think that this is any solution to overcomming warriors or rogues, try a new tactic to over come them