I don’t think they would. Captain can still be the abort authority and call it out, so it shouldn’t change the rate of rejects.

The only thing changing is the PF remains the true PF (including thrust levers / power levers / throttles) vs exchanging controls mid RTO. This is a much more stable operation in my opinion and the way every operation I’ve experienced outside the airlines fly.

The tiller shouldn’t come into play either as we are generally planning to stop straight ahead on the runway. Most modern aircraft have more than enough rudder pedal steering and braking authority to do that. In fact, tiller steering at high speed can and has caused loss of control accidents too. I haven’t flown all of our current aircraft fleets…do any of them require or even suggest tiller steering above taxi speed?