Don't hold your breath on RTM.
I suspect FlyBe will dip their toes in the water at MAN for a few months before realizing it ain't going to work then letting the whole thing slip quietly away.
Anyone that travels to Rotterdam knows full well the best way to get there is to fly to Schipol and get the fast train directly into Rotterdam city centre - in next to no time. The volume and frequency of flights to AMS ensures you get there at a time that suits you rather than a 2-daily RTM. Flying to AMS will also be cheaper.
FlyBe will effectively be competing against their own AMS flights.