I remember years ago there was a talk about a feature to include your own, developer-approved characters if they were good enough. Not sure about its state right now, or how it was supposed to work in the first place for that matter. Would it be included in a patch or something? Or only available for the creator of the character? Optional DLC? These are the questions the devs should answer (aka we'll never get the answer).
But from the dev team I think you can expect mostly just bugfixes after the release, leaving additional content to the community. (If there's any left by 202x).
Mod support would be great, though. (And I mean actual mod support, including client side.)