Here's my non-flame-bait educated guess on how this will all play out.
5 years from now:
Midwest brand, service, name and original hub (MKE) gone. Midwest Legacy crews all gone, in part due to the awful deal they will get on the integration, and the fact that Republic as a whole will shrink.
Fleet reduction, most 50 seats gone, some 70 seaters gone. UA and DL don't renew due to the obvious competition that the new and improved Frontier will bring into their markets. Most buses will go away and replaced in some ratio with either 190's or BB's new toy the C-series.
Frontier is the new name for all integrated branded operations. However, due to continued pressure from other LCC's (SWA, Airtran, possibly even JetBlue), the business model shifts from a service driven product (Legacy Midwest, current Frontier), to a wholesale lesser quality product.
End result:
RAH will be about half the size it currently is, but still around. Most Frontier and Midwest Legacy crews gone due to decaying QOL, pay, and issues with SLI. Most of the buses gone with a 1-2 or even 1-3 ratio of replacement. Most market share shifting over to Airtran and Southwest. All and all, a bad thing for everyone involved and everyone in the industry.
Uptimistc (yet unrealistic) result:
SLI goes through without a scratch, everyone is happy, the company thrives without much resistance from competition, and the new and improved Frontier integrated pilot group negotiates an industry leading contract.
Time will tell, again, this is just a humble opinion, and educated guess.
goaround