Honestly it's more than just the roof, otherwise I doubt they would have any issue spending the hundreds of millions to renovate the roof instead of the hundreds of millions more to replace the whole arena. The Saddledome just has too much out of date compared to a new facility to make it worth renovating. Not enough loading docks, a small club area, shallow lower bowl, outdated interior spaces, only one concourse, not enough bathrooms, a small event level, not enough office space, no elevators (without club/suite tickets), no escalators, no full sized team store, etc.