Beyond student sparring sessions, Whis tends to not involve himself in fighting, so the opportunity to see the depths of his power has yet to present itself. Some people are content with continuing to follow the Beerus (10) and Whis (15) power gap established for the BoG film since nothing contradicts it yet, but Super could widen it if desired. Promotional material compares Broly to a God of Destruction, but it's also been expressed that the more he fights the stronger he gets, so in response to the question: it's not outside of the realm of possibility, but at the moment there isn't enough to go off of to say it will be likely.