I got an email from WMTV with a little more information about their signal and future plans:
We have an FCC construction permit for increased power and antenna height. WGN-DT is a problem to our SE, but reverting back to channel 15 for digital was a bigger problem due to interference with channel 16 in Rockford, even closer, requiring us to REDUCE power if we went back to 15. The power increase is for the maximum allowable with no interference to WGN-DT at our mileage separation.
Once we can begin disassembling our analog transmission system we can begin working on the digital power increase. That's about all I can say at the moment.
what might happen:
Looks like the FCC never gave WMTV a good choice of digital channels, but it does seem as though they will increase power. This will help many viewers. It seems like the digital power increase and better tower will happen the same time the analog shuts off. From reading at nbc15.com and another source it seems they want to save money by not having analog up in the air, but they want to upgrade their digital before they completely convert (also costing money). I suspect the change will occur after Feb but before June?