Just throwing this out there, not saying if I think it's a good idea or not, since I'm really not sure:
Forbes estimates the value of the Flames at 451mil as of November 2014:
http://www.forbes.com/teams/calgary-flames/
Accepting that KK et al are contributing 450mil to the 890mil + 50-300mil remediation, they are asking for about 500mil in public money at least. That's more than the value of the Flames franchise.
If the public is putting up more than Flames are worth why shouldn't the City/Province/Feds whichever level of government(s) is involved in making this happen, get to own - as the silentest of partners - 50% of the Flames, or even 50% of CSE - and get repaid through revenue and then CSE gets an option to buyout the public ownership once the money is repaid?
In the end CSE gets the shiny new buildings, and the City gets its money back, and both organizations have huge incentive to do everything as efficiently and as profitably as possible.