If I look at the roadmap I see all kinds of improvements that are interesting but it's not the things uses want (I think),
Not what users what? What are you talking about?
Users want: caustics, clearcoat, fixed volume media, removing portals, cryptomatte, and more.
I think when you said "it's not the things uses want (I think)", you actually meant "it's not things I want".
I'll be blunt. The whole race, since the beginning of CGI, is to make the most realistic image possible. That's what you see people do and admire when somebody is making images that are next level in realism (and also in beauty, but that's dependent on the user not the engine). So the MOST important thing for a render engine is to keep up with what's technical possible. At the moment Fstorm is producing more realistic images than Corona, don't ask me why or how, I'm not a technician, it just does. So I think that the most important thing for the Corona team is to improve the engine to be on par with the best. I think THAT is the most important thing to work out now, and that's not in the poll.
The whole reason I switched, a few years ago from, Maxwell Render to Corona is that Corona is better (read more realistic and faster). If you ask me, Maxwell is nice but it's dying out because they did not improve their render model and kept to the physically correct rendering of light. I love corona(!) so I would hate to see the same thing happening to them so I really like to see that they keep improving their render quality so it still on par with the best, as they used to be a few years back.
I know a lot of people not going to agree with me because this might be too bluntly said, but I think that in it's core this is true. People will eventually chose for what's the best quality. :)