I think it's better to put it under a centralized commission with all sorts of fairness rules on who gets to participate, based on things like percentage of votes received in the last election, whether you have an MP in the House. Take away all that discretion.
Having third party groups run things, some would say would balance it. You'll have different groups running it. Some will have a certain slant and run it that way because they have an interest, and others will balance it by having a different slant. I think it's better to put it into a non-partisan commission.
I know Elections Canada itself doesn't want it, but it can be a commissioner under Elections Canada, just like the enforcement is now, and have all sorts of fairness rules. The broadcasters are using the public's airwaves. Require them to air it on the public's airwaves. They already gouge us enough and use the airwaves as they want. The airwaves are a public resource. They're licensed to do it. An election is important. The debates should be running on all the broadcast outlets whether they want to run them or not. That should be what's on during prime time that evening.
I think that's the better way to go than grants and contributions.