Good news is, this is next on the test program. They'll be testing the "belly flop" with this vehicle in the next few flights. So they'll see any problems with

Good news is, this is next on the test program. They'll be testing the "belly flop" with this vehicle in the next few flights. So they'll see any problems with it before they get too far. I don't see much reason to be worried about changing orientation in the long term. It's not in a particularly exotic flight regime (subsonic, lower atmosphere) and so long as the vehicle has sufficient control authority (and it will) anything that would cause that maneuver to fail would cause any other maneuver, like landing, to fail as well. The F9 actually already does a (less dramatic) version of this, and has never had a problem in that phase of flight.