On the other hand, if the system could land with all stages, it could mean that it was cabable of intact abort for a large portion of first stage flight. Just l

On the other hand, if the system could land with all stages, it could mean that it was cabable of intact abort for a large portion of first stage flight. Just land back to landing pad. Hairy aerodynamics and balance issues. F9 has enough engines for very good engine out redundancy. I don't know if the "landlord" could accept flying towards ground with lots of propellant. For later portions of flight, abort is an abort to orbit. But eventually some such early abort capabilities will need to be incorporated when flight rates pick up. A robust system will not destruct in case of relatively minor problems. Twin jets have enough thrust for single engine ascent with full fuel. This necessitates a huge rudder. But the planes live with that.