Don't forget aerodynamics. Shuttle suffered from all sorts of buffeting that a smooth cylindrical rocket would not. The complex shape also meant more unpredictable asymmetric vibrations. A liquid-fueled shuttle would still have been a rough ride.

And shuttle took a much more aggressive path. SpaceX rockets aim very high for longer burn times (more up, less sideways on first stage). It is technically a less efficient approach but allows for the recovery trickery.