Hope to see more developments on mobile related features and optimizations. Where I am from, people mostly use mobile devices to surf the internet and many use low-end mobile devices. I really like Discourse but I find the mobile side of things are a bit lacking although I have only tried Discourse for just over a week and so I may be judging to early.
Just to compare with nodebb which is quite similar to Discouse and maybe the only alternative that one has of a modern forum software. It has some mobile specific features which I think would be good to be implemented with Discourse such as full screen text editor when writing topics or posts. In addition to that, the load times are better with mobile, at least that is what I experienced with my phone.
That being said, as far as I know no other open source forum software can be compared to Discourse when it comes to development activities which to me outweighs these concerns and one of the main reasons to choose Discourse over other softwares. Although, it would be nice to have better experience on mobile.