​Is there anything next after the "Dead or online" update besides balance changes? Any new content or big gameplay changes in the pipeline? I feel like you guys have a good base here, but player count probably isn't going to go back up without some big changes.

Nope

I enjoyed the Viggie update and would like more content as well.  I like her unique crowd control and the fact that she can hover over most any hole in the floor!   There is plenty of room for new characters, different modes, and perhaps an additional floor setting and boss.  

Fix to non-disableable Core Stellas would be nice.

Honestly this game has a great core to build up on, strategy, planning, combat, problem solving, cool characters, good amount of weapons, perfectly implemented rogue like elements. I really hope they do more or release a sequal.