The lack of training about the implications of rejected landings and especially the changes to the auto spoilers, auto brakes and autothrottle responses and indications is very significant. Given that we almost never saw these situations on line, an exercise during the triennial cyclic matrix would have been valuable.
A massive human factors fail was the fact that nobody knew who was flying after the attempted G/A. Had even idle reverse been selected the outcome would almost certainly have been OK, a bit scary maybe, because the auto spoiler would have extended the spoilers and enhanced the braking enough to stop her.