Calipers with integral parking brake are not my favorite either.  Given a choice I'd prefer a Banska style where there's a small drum inside the rear of the rotor.  Every vehicle I've had with that setup never had an issue with the parking brake.  I believe the Explorer rear setup uses that style e-brake.

That said, adjustment seems to be the biggest issue with the calipers with the integral e-brake.  Most of the factory systems were either not adjustable or supposed to be self adjusting.  Over time the cables stretch a bit or other things wear and the brake becomes less effective. 

Regardless, I don't think the solution is to introduce another level of complexity into the system.  I'd look to remain mechanical in some fashion vs. electric or hydraulic.