As a Mechanic that works the MD90 and MD88. I much rather see the MD88 stay and the 90 leave. The MD 90 engine and electrical systems are alot more difficult to work on. Just the fan and core cowling alone takes about 15-20 minutes to open with 2 people .
The 717 is notorious for hot brakes on turns less than 50 minutes. We automatically roll out the mobile brake fans whenever they visit our station in BWI during the summer. No other plane in our fleet needs this type of attention.