If your going to plant a flag at a regional, make sure your in the top 2/3 of the list or better if you want some QOL in the future.
The AA scope changes will likely be renegotiated in the future and the UAL and DAL regional fleets are shrinking. It may not be apparent now, but it will be soon.
The drive in this industry is towards bigger, more fuel efficient, densely seated planes that sell more stuff per pax and remove 50 seaters from the air.
Take a look and find a 76 seater that can cash flow on non-dedicated regional routes like a 737MAX or A320NEO. I'd love to see your spreadsheet on an EMB 175 76 seater vs a 737MAX or NEO at 150+ seats. There's gonna be quite a few routes where the EMB wins at various fuel prices, but not as many you think.
As fuel goes up and up, the smaller jets choke. Too much gas per pax dollar. No tickie, no washie. Now, if they can get that Q400X to work, thats a whole different ball game.