Think businesses would bite? Month-to-month, no minimum, cancel any time is so much in vogue, it's hard to imagine there would be much traction around a multi-year contract, but maybe I'm wrong.
More generally, it's one of those things that you don't want to change if it works well. Maybe the best model is an short term contract (e.g. 3 or 6 months) which can roll into a multiyear contract.