Im just going to assume that there will be atleast a 4 player coop. However, ideally there should be some scaling mechanism that you can turn on/off. So lets say the game is balanced for 4 players but then you can have up to 6 players or just play it solo and the ECL would scale just like in the PnP (not sure ECL is a thing in 5.0e, im a 3.5e player).
No idea how much work that would requier though.
