My fear is that, since the A319s will hold only 7 fewer passengers than the MCE S80s, we'll start seeing them pop up on high frequency routes currently operated by the S80s.
I fear that your fear is very likely the exact reason that AA ordered the A319s.
When they were ordered, I wondered why AA was all alone in ordering small narrowbodies while US was replacing 737s with A321s and even WN was substituting larger 738s for its 73Gs.
Of course, I was incorrectly assuming that they'd be configured in a civilized 12F/30MCE/72Y that totals just 114 seats (MCE all the way thru the exit row).
Now, it all looks a little more clear: for those 3-4 hour routes where the MD-80 featured a few too many seats, AA will now have a more fuel-efficient replacement. But just 8F? Even Doug Parker's US, long known for small F cabins, features 12F on its A319s. And for many years, the bulk of the MD-80s featured 14 F seats (before 100+ MD-80s got 20 F seats to facilitate upgrades). 20 or 14 or today's 16 down to just 8?
