If the league wants to continue to grow, it can't go back to London for at least another 3 cycles (9 years). Sure, they might be able to pony up the most right now, but there are other viable cities that haven't seen this tournament in years (if ever) and if they want to build the popularity and demand they need to spread it around.
If I were running the league my next four would be Barrie, Kingston, Niagara and Sarnia. Then I'd go back to Windsor (assuming no new rinks in Owen Sound or some of the other yet to host cities). My unbiased order would be as follows:
Kingston (2014)
Niagara (2017)
Sarnia(2020)
Barrie (2023)
Windsor (2026)
My biased order would have Barrie hosting next year, and flipping with Kingston.
This all assumes quasi-competitive teams in the bid years, so may require some tweaking, but I'd be trying to move it around geographically while moving through the teams yet to host.