I think Commerce is one of the most useful features in IPB. And I love the fact that it allows for community members the opportunity to upload files that they can sell and make money from. However, in the future, I see two nice ways to improve upon this and take it to the next level.
1) Allowing the sale of physical items as well. Yes there are 3rd party plugins that can be used for that right now, but it would be great if it were just apart of IPB.
2) Stripe Connect! Right now, when a member sells a file, it's too much of a tedious process to get their money. It goes into their account as credit and they have to withdraw it. And for people like me who don't enjoy using PayPal, it discourages me from even allowing my members to sell anything. However, an implementation of Stripe Connect would allow for a much smoother experience on both ends. A sale is made and the member instantly gets their money. And I'd recommend utilizing the easiest method of the 'Standard' account type - https://stripe.com/connect/account-types which simply adds a button into a common sense designated area that via oAUTH, they quickly create a Stripe account, connect it to yours and they're redirected right back. Very simple and just nicer.
Just my two cents.