Montreal does have some things going for them, chief among them being the lack of numerous alternatives for the Rays if they do intend to move. Lets look at some of the potential markets
Another team in Texas, San Antonio? SA's a pretty big city but their metro population is much smaller than Greater Montreal
Another team in California? Pretty much out of the question, there's San Jose but the Giants would object and A's have been trying to move there for a while.
A team in North Carolina? no densely populated metro area, another problem being that NC is a bit like Florida, there's a lot of Northeast transplants that already have allegiances not to mention how dominant college sports are here.
New Orleans? Too small of a market
Portland? Too small of a market
Vancouver? Too small of a market
Las Vegas? Probably the most realistic outside of Brooklyn
Another team in the NY/NJ area? ,pretty realistic, another team in Brooklyn could be possible, there's some possibilities in NJ too
Montreal will have competition but the big thing is whether they can get an ownership group together, i can see Bell being really interested, give them a chance to finally control some content on their own.