I think it'd be better if the probot was launched from a terminal and remote-controlled like in That Other Mod. Would allow for people to control it, instead of it just sitting there until it gets shot.
If it can be given a decent AI, though, I'd not see a problem with it controlling itself, spotting enemies and exploring, as it should.
As for deployable sensors, why the Heck not. Give us more deployable stuff, from E-Webs to ammo boxes to sensors. Forgotten Hope and the Ground Control RTT got me hooked on deployable stuff.
"One of the bitches actually gave birth while she was attacking, and her puppies joined in on the carnage."
--the awesomeness that is Boatmurdered.