IMO it is not a step back but , in fact, depending on the content it will be a "step forward" if sports are being broadcasts. The future will probably bring systems that adapt to the show content on the fly so it switches to 720p while hockey games and back to 1080i for lets say The National. I was also used to 1080i and I remember when WNED went to 720p as well , but I do not see much of a difference. This is all mostly subjective matter. ABC and FOX use 720p for that sport reasson , look at their presidential debates , CBS at 1080i still blows away IMO the rest but ABC is just behind them , at least for my eyes, lol. Besides, and more important, the final transmitter could well be 1080i but if to get the signal to the TX site they have to overly compress it (like the ones that use Bell TV or Shaw signals) rather than dedicated properly set links (wide bandwidh links on Sat TP or Digital Microwave or even better fiber optics) then what is the point fo 1080i anyways?.
If not for the cities and towns left in the dark and the lack of PSIP EPG in Toronto still , I would have given the CBC a 5 star rating for their digital conversion.