Oh the arena is purely PVP, I doubt they would do anything else with it.. gotta draw in those pvpers some how. I like the idea of monster hunting, but again I don't see it being a thing. The Divinity Community is strongly against any form of mechanic that might add monsters to their world! -_- trust me.. I went through all this on D:OS 1 forum. If they do take a look at your idea and it's something they implement or some form of way to enjoy the game without just rushing forward..they would have my money as long as they want it lol.
Larian (Swen) always said that what ever they do with multiplayer, single player will still have a much better experience as the majority of people only play in single player. They already have a mode like hunger games (work in progress) but for single player I'm sure we will have modes like waves, levels, and so on.
I am also hopeful if these suggestions will be added as I think it's a good valid point that areas tends to go empty when you have explored, interacted with everything then move along.
Though yeah I know what you mean with the community but yeah my suggestion will work as it does not force the players to do these quests, they are more like activities to do more in the world
