Another Open Source software product I use struggled with development for a while. Of course the developers time is valuable and no one expects a developer to just work for free. They came up with the idea of a "Make It Happen Campaigns". These were features that seemed to get the most requests but the developers just did not have the time to devote because they were intensive items. So what they did is set up different campaigns where users could donate funds to support the feature they wanted most. Each campaign would be fully fleshed out and a quote for the amount of time and amount of money it would take to fund that particular feature. Allowing users to each donate $5, 10, 20 or more dollars toward a particular feature allowed the features to be implemented by paying for the developers time to implement them and made the load less burdensome because many people were contributing. https://en.wikipedia.org/wiki/Feature-driven_development
I think this would be an excellent way to get features the community wants into the system without creating a heavy burden on the developers.