Instead of trying to please them asses, errr, sorry, that's "please the masses", would it be better to tweak the mission machines to allow all players to select their own destiny?

The main difficulty slider could be changed to "close / distant". That would select the distance to the mission. The other internal sliders are good to go if tweaked to work. Maybe add one called "entrance difficulty" or whatever and let it select the difficulty of getting in to the mssion and would determine the numver of MOBs a player would face to get in to the mission.

Then use the combination to assign mission choices, pay-outs and prizes for completion.

Another suggestion would be to allow the mission goal to be picked up at any time but to not give a token until the mission is completed. In other words, if all MOBs are not downed when the player leaves the mission then there is no token. Of course, the ability to store the map would make this unnecessary as the problem is losing the map if leaving to heal.