MKE-IND had nonstop flights for about 40 years until it ended in 2012...first by DC9's (Ozark and later USAir) and then with a flock of 19-34 seat props. I believe it peaked at 14x/day in 1994. With regional jets it was a busy route for Midwest/Frontier and also AirTran RJ's, but with the demise of those hubs pretty much all MKE's regional flying is gone. That's unfortunately but it's something seen all over the country outside of the remaining mega hubs.
OneJet seemingly got a lot more publicity in Milwaukee than in Indy when I look at online information. Considering that the initial schedule is completely designed for Indy-originating passenger hopefully that's not a bad sign.
For MKE travelers who go the night before to be at the client first thing in the morning we could still use OneJet on the way down. But most likely the return would need to be on somebody else. I'm definitely hopeful they add a flight for MKE traffic as well.