The last few years DTW/YUL fares have really gone up. And I think now all the planes are RJ's with no first class, so no upgrade possibility.
YYZ is also really expensive. It's a LOT cheaper for me to just drive to windsor and take VIA rail. I can ride in first class on VIA for a lot less than it is to fly and I also save a lot of money on cab fare since I get dropped off downtown.
Did you try checking porter air out of windsor?