Sales leadership should know that they need to build a sales team capable of selling what you have now while providing a vision of the future. Just guessing, but it appears they are caught up in trying to sell using features rather than selling your product as a solution to the problems your potential clients have.
If they can not sell the solution and keep getting caught up in a feature to feature competition, your company is in significant trouble.
That said... the feedback from potential customers, new customers, current customers, what you see competitors doing, your support organization, and the engineering team plus your vision of what the product needs to become are all critical for you making decisions on what to build.
As many here have said, there is much more to your question than can be answered here. I'd be happy to talk if you'd like to.
By the way, I have a single KeyNote slide for our roadmap. Not fancy, but it is simple, cheap, and gets the job done so we can focus on the product.