Seven years ago the entertainment venue was announced as having 5000 seats, then later reduced to 4200, and apparently now back up to 5000? https://greatcanadian.com/toronto/
The image shows the seating to be the same college gymnasium-like arrangement (and mentions sports events) as the multi-purpose Rama and Pickering venues, with a flat floor and straight grandstand. If that's "state of the art", then the art isn't in a very good state. It's disappointing, since I was hoping for and expecting a theatre like the new 5000-seat Fallsview venue with sloped orchestra and curved balconies. Toronto has lacked a venue like that for as long as I can remember, while we have no shortage of arenas of various sizes that are poor concert venues because they were built for sports.
Edit: BTW --Though not ideal, a big theatre can be used for sports requiring a floor as large as a basketball court if the stage is big enough, as shown by Radio City Music Hall.