I’d actually like something like this, though probably not quite as simple as this. I think some backgrounds might just not work together well (Killer on the Run + a monk, or an raider fighting alongside a caravan guard?), so they’d develop cohesion slowly. Others may develop it more quickly (the militiaman and the old veteran; the squire and the adventurous noble; the bastard and the disowned noble). It’d have to deal with that and random events if it were included, IMO.