I'm sorry, I've fallen into the trap of all the merger and partnership ideas.
I was thinking, a partnership (not merger) between WestJet and Midwest may not be such a bad idea. Currently, WS flies all 737s. -600s, -700s, and -800s. YX is running with an entire fleet of MD-80s and 717s, however, they are looking at the purchase of new aircraft (This whole thread lies on the assumption that the 737 becomes that aircraft).
As for routing, YX serves out of MKE to nearly every major airport in the eastern USA, and a mediocre, but solid number of cities in the west. In the year of 2007, they are opening 6 new cities, which I hope to include SEA and SLC. However, the Canadian destinations are sadly lacking, with YYZ being the only one. On the other hand, WS is serves out of YYC to nearly every major city in Canada, with a special concentration on the west coast. They also serve to multiple cities in Florida (and even NAS), two in Hawaii, and few in the southwest. They have yet to fill in the space between. Perhaps YX can do that for them, and WS can create a Canadian plan for YX.
Last, there's the overall plan of the company. I myself work for YX, and I have a friend who works for WS, and it seems as though many of our conversations result in common ideas about our companies. From my view, both YX and WS are smaller airlines, but just as well known. They are known, however, not for their size or number of flights; they aren't only about growing bigger and flooding the market - but about care to the customer. They go the extra mile to try to make the customers' experience enjoyable.
I lay this topic down at the hands of my peers, and hope I don't get ripped apart