Unless you are talking about a CR2, I have no problem with the CR7/CR9/E170/E175 (though prefer the CR9/E175 for upgrade opportunities).
Flew it this year on RDU - AUS (about 200 miles longer than YUL - ATL) and was perfectly fine and fly them all the time on the admittedly shorter RDU - JFK/LGA/EWR routes. Row 5 is great for C+ and FC upgrades are often plentiful, especially on RDU - NYC.
I'd have a hard time believing that any seat on the MD90 has more legroom than row 5 on the CR9