So to all of the people claiming the MD-88's are terrific and an upgrade.
Last summer, I had 12 - yes, twelve - MD-88 flights cancelled. One of them was a diversion to Dulles that made the news.
I don't have a Flightaware premium account, but at one point, found over 15 diversions, delays, and cancellations (RIC-ATL among others) related to MD-88 maintenance issues.
Here's my problem - Delta is running MD-88's (back-to-back-to-back-to-back) like Southwest runs 737's (no MAX comments, please).
This = delays and cancellations due to simple issues that I personally (small data sample) haven't experienced on the A320 nor A321. Door issues. Wing/flap issues. Tire/wheel issues.
Why else would Delta run the A321's on "higher-value" routes? Yes, I understand increased capacity - but even the "ceo" (current engine option) has been more reliable than the MD88.
And finally, yes, the MD-88 mainline craft is better than a regional jet for planning purposes. But while Delta nukes a whole ton of regionals during IROPS, MD-88's give false hope. They're still cancelled, and I'm still stranded overnight.