The fact that you remove the franchisee's opportunity to finally get in a good standing of profit making by forcing a new look that customers' reviews says is not good.
The forced new look and the debt that comes with it.
Consult with franchise owners who are in the day to day when creating a new design & set up. Also, give owners more that 2 years after they've paid their notes to get a better cushion to operate from. Especially since costs of goods/min. wage are increasing at greater rate than profits.