I would rather have physics as the number 1 priority...
I do not know if it is due to the physics, or just the design of all the FWD cars I have tried in rfactor 2, but I struggle a lot finding good front wheel drive car in rfactor2... and let's not mention AWD (but I would like to try those too..)
For me it is just not right how the Honda Civic BTCC and Renault Clio behave.... but not only regarding force feedback (as most of the people complain in forums), as also tire degradation, turn-in response and several other things.
I do not have a huge experience, but I did drive FWD cars (Still drive them though), and even racing FWD (although it was nothing extreme as the BTCC Civic, but they were pretty close to the Clio... less hp but lighter cars)... and it is day and night difference
About the content we actually have is pretty good... there are a lot of tracks, a lot of leagues have their own tracks, we have certain tendency in including DLC Endurance Series cars (there are pleny of them, specially GT3 and GTE class), but we also enjoy of the new pack of Tatuus (with enormous possibilities to choose between).....
I believe that there are more than enough good cars, and a good variety of circuits, specially the ones related to endurance series... I can even live with the current UI... I am used to it at least.. hahaha
so the the obvious answer would be to focus in physics....
but I do not see the near future with physics DLC (it is possible, but difficult), so the easiest way to do business I guess it is by selling cars and tracks in DLCs