At this point I think the MLSE has already over extended itself with the purchase of the MLS franchise TFC. I appears to me that making a turn around for the franchise on the field will be there priority. The lack of attendance would have much to do with there very poor play and records.
Also getting their focus back on making the Leafs a Stanley Cup Champion. Those fans will come and support no matter what as one of the original 6 franchises plus a some of the new franchises over the years have a strong wupportive fan base no matter what.
I think that the Argos conversation came to be about simply as a way to get the renos on BMO to be paid for by the govt. As they found out though bringing the Argos and the CFL to BMO may isolate the loyal supporters of TFC.

There simply is not enough support for the Argos from those who live in Toronto and there will be no $$$ from govt to build another pro sport specific stadium.
I am going to stick to my opinion that moving the Argos out of downtown and into a GTA Region and Municiplity is what is best and has been prove to be a recipe for success in every major city in North America that have 5 or more pro sports franchises. NFL, NHL, NBA, mlb, and MLS all have venues outside of the city and into what has become highly populated Metro regions ans well as stadium in areas outside the city with excellent access from many roadways to the stadium from all parts of the metro region.
For the Argos it will be more about bringing the CFL and a pro sport to a well populated part of the metro region outside the city where there are currently 5 teams home playing venue within 3 miles of each other of the downtown section.
JMO of course but this would be the first time that this has had to be done in Canada as Toronto has grown into one of the biggest Metro regions in North America and the first Canadian one to have 5 pro sports teams.