Firstly, emphasis on RP does not conflict with "having a game that is fun to play and can withstand different types of players". It might conflict in your eyes, but that's just you.
Secondly, the game code is open-source. Actual content like the art and the quests are not, nor will they ever be made open-source. If you find certain errors or bugs in the quests, NPC responses, or the general settings, then you can forward your input to the devs via the Forum (special thread), the bugtracker or via PMs.