One factor which I have never heard mentioned in terms of media coverage (which I will mention now) is this...

Of the professional sports teams in Toronto - Maple Leafs, Marlies, Raptors, Rock, FC, Blue Jays, Argonauts (The Wolfpack are too new to impact this discussion imo) - which play the least amount of regular season games?
Answer: Rock and Argonauts.

My point is that the teams who play ~ 80-160 regular season games will automatically get more media coverage by default, if only because there are games to be covered and highlights to be shown more frequently.
By no means is this the only or most important factor - fan interest is most important - but it is a factor nonetheless. Even though TFC does not have a broad following outside of its core fans who actually attend the games, they still have 34 games which are covered on TV and radio sports reports. The Argonauts (and Rock) only have 18 regular season games on which to report. Conversely, the Blue Jays play almost every day from April to September, while the Raptors and Maple Leafs play every two to three nights.

I think this is a factor in terms of media coverage.