I wouldnt get all excited about more 70 seat jets at a regional anytime soon. If you have talked to a CAL pilot lately they arent rolling over on scope. It is going to take a bankruptcy for management to get scope relaxed and that doesnt look like it will happen anytime soon. They need both pilot groups to play nice and management should be willing to give them something to make this happen. Stopping the flow of jobs going to regionals should be their #1 goal.
As for who would win or lose flying it is a complete gamble. I wouldnt neccessarily dog any airline (regional or major) in this fight. Any 50 seat regional contract can be renegotiated on a 2-1 deal for a larger aircraft. I will bet money that if CAL and UAL merge and scope gets relaxed that XJT, CHQ, Skywest, or even Mesa will play ball with management to "right size" the fleet. In XJT case Does CAL want to continue paying out a 50 seat contract for 5 more years when they could get 70-90 seaters?
Who wants to retire at a regional? not me. Screw the "regional" jets and lets get that flying where it belongs.