Not that I'm any expert, and even though I really like HG, I think that the userbase and development at this time is to small to be able to make money from it. No one than me would be happier if Gene could continue and make money on this. But it would be sad if it wasn't open source anymore.
Because of it's possiblities to customize HG so much it is very powerful. But it also demands a lot from a new user without much skill. Some things should need to be much easier, but still maintain the possibility to be customizable as it is today.
One way, that I would think could be good, is if it was possible to get good support for MySensors. They try to take IoT to the ordinary users that like to fiddle a little. They have very good beginner guides to use Arduino to make wireless sensors. From easy things to more advanced. I've tried several controllers but they often are so specialized that MySensor sensors don't really fit. And instead of the possibility to adapt the controller you have to cripple and adapt your sensor sketch to fit in the controllers small box.
Good support for MySensors and "easy" ways to make custom widgets in HG for MySensor sensors would be a huge thing I think. And could increase the userbase very much.
I still haven't given up on my goal to be able to contribute more to HG, but recently moved to another country and all hobbies have been put aside for a while. I really hope we can keep HG alive in both forum and development.