The best things about Canoe are the views (you can see New York State on the horizon on a clear day) and the bar when Jeffrey is working there. The food is sort of high-end meat and potatoes and the crowd tends to be the downtown financial community, at least at lunch. I think it's more fun to eat at the bar (on the stools facing the south windows) if you're going to go there. You could have drinks and a couple of appetizers before the play. Then you could have dessert somewhere after the play.
If you want a blowout Colborne Lane is a lot more interesting - Claudio Aprile does a great take on molecular gastronomy but it all works nicely and isn't silly. Have the tasting menu and the wine pairings. Other blowouts would include Opus for the wine list, Chiado (serious Portuguese resto, wonderful seafood), Frank's Kitchen (I haven't eaten there yet but it's getting rave reviews), or Scaramouche (great views - demand a window table and don't go if they can't accomodate. Maybe the crowd skews a little old but it's a first class kitchen and professional service, which is not a given in Toronto. You'd need to cab it.) However none of these would be pre-theatre spots.
It's kind of restaurant row along King across from the Hyatt, but most of them are forgettable.