Once the transition takes place, the stations will no longer be able to run at half power, maybe that will help your channel 19, or maybe they just don't have the power needed to send thier signal out, but you would think that it would be fixed when the transition takes place, when all stations are required to be at a usable power level.
19 will probably still be the worst for OTA reception. The are already on their post-transition assignment: Ch 10. I think they are currently at a weak 3.5kw. They will be going to 10.3kw. For comparison, 2 channels down on 8 (WJW will be moving back to the old analogue 8) will use 30kw.