I see a lot of mention of the same cities that
Express Jet has already announced service to (they'll be flying to AUS, RDU, MSY, JAX, SDF, ONT, and TUS non-stop from MCI). I'm not saying that Express Jet is a major concern to Midwest, but it certainly makes some of these routes less attractive with another carrier already offering non-stop service several times a day (3x daily on an ERJ is going to be a lot more convenient for many travellers than 1x daily on a 717), and if they try to go against Express Jet with CRJ's ... personally I'll take an ERJ with it's 1x2 seating over an CRJ with 2x2 seating any day, and as for service, Express Jet has said they will be serving meals on their flights, something Midwest only does for a fee.
I know they've announced they're adding six new cities, but I personally prefer them beefing up service to cities they already serve where possible, that's more valuable to me than 1x daily service to new cities.