Au contraire - if the droid is made weaker, people won't use it for combat. That's a key distinction - Probe Droids are not (unless I'm seriously wrong on my lore, which I might be) intended to be used in battle - they're intended to scout, and they have weapons primarily for self-defense. In the context of the game, we wouldn't have people spawning en masse at the base and rushing for the droid launcher - instead, a squad member would grab it and help out his squad, or what not.
This is the same argument for having Medics and Support characters. Their guns are weaker than a standard Trooper weapon, so why would anyone play them? To help out their squad, of course. Same with the Probe Droid - it should support the team by scanning the area, not by anhiliating Rebel squads.
At least, that's my (not so) humble opinion.