"planned for AW4 to get rid of the relaxed realism flight model and the multiple arenas and just have one main arena using the new flight model"
That's my understanding also. Except it would have made for one very large RR arena. The new super, dooper complex FM had training wheels being welded on inspite of it's "Ultra-realism" tag by the AW-4 team. Not user selectable automations. Features neutered for, as I recall, the reasoning being that the AW4 team "knew" that players didn't want to tackle much of a learning curve nor have to deal with "tedious chores" and other "b.s. realisms."