TFC has the best TV ratings in MLS.
Think of TSN2 (and SN360 and SN1) as the local TV partners and TSN as the national carrier. So far, the games on TSN match or exceed US national TV ratings. The first game of the season SEA-SKC got 330k viewers on NBCSN. In 2013, games on ESPN averaged 220k and ~110k on NBCSN (pathetic, I know). 2012 was MLS' best ever year for ratings, ESPN averaged 311k and NBCSN 125k.
Local TV ratings are much worse. In 2012, Seattle—which I believe has the highest local ratings—averaged 45k and 33k on their two local affiliates. NYRB had 25-30k viewers. 9:30-11:30 pm on a Saturday is a terrible time slot, so a significant drop in viewers for the RSL game was expected. But even if 74k is the average for non-TSN broadcasts, we're still well above league average.
It's embarrassing really how bad ratings are in the States.
I'm not at all surprised NBC is dropping coverage next year. In contrast, the ratings in Canada are great. Unlike the US, more people actually watch MLS than EPL. I'm really interested to see how what the ratings will be for Vancouver this year. They have every game on TSN/TSN2 except one on CTV BC the rest of the season. It should do wonders for building an audience.
Sources:
http://grantland.com/the-triangle/ar...on-television/
http://thebiglead.com/2013/11/12/mls...-improve-them/
http://www.sportsbusinessdaily.com/D...Media/MLS.aspx