I'm not sure why the 321 deliveries are used to make a QOL argument in the near term. Yes they will have great layovers...when they get delivered in enough numbers to where those trips are junior enough to get them. I think the latest projection is 12 at the end of this year and 31 next year. I wouldn't be shocked if it's ~2 years from now until you can even get those trips. So if layovers are a big deal to you why go to the bus now and wait ~2 years to get those sweet layovers, when you could fly something that already has good layovers until your seat lock is up and then just lateral over to the airbus?
Also have they even announced which bases would get the most 321's? I assume it will mirror the 756 footprint but I haven't heard the exact plans.