It could stand on its own with a Combat Maneuver build, which needs Int for its feat progression anyway. With the right traits, you could also use it as a more martial and less sneaky skillmonkey than your average rogue. That said, it definitely seems to be a dip class to me, except it trades the bardic stuff for BAB.I was going to say 'multiclass fodder', but you essentially beat me to it. That said, I don't think the issue is whether it's overpowered, but whether it can stand on its own.
It kinda does what Inquisitor does, albeit without magic. I was thinking something along lines of a Bard(Archaeologist) multiclass with it.