As far as the single player campaign goes (won't touch any of the tweaks and changes that should be made to online since I simply don't play it enough to have a legit opinion) a proper ending would be satisfying.
It's not like this would mean the end of the series as Guerrilla has a huge amount of area to cover in the KZ universe/timeline and that's without even touching what many players would like to see: a Helghast campaign. I don't know if it's just me, but it seems like more players prefer the Helghast over the ISA even though they're the "bad guys" modeled after post WWI Germany. They have better gear and uniforms anyway.
Maybe if the Helghast hadn't been written to be so monstrous (using POWs for weapons experiments, etc.) and the entire Helghast/ISA conflict had been written to be much more ambiguous, this wouldn't be an issue to the watchdogs who would raise a red flag over putting the player in the role of what are basically Nazis.
An online co-op campaign would be a welcome addition. Making the co-op campaign the default with Bots for stand in players when playing solo would ensure that the campaign was the done properly without being simply an extra tacked on play mode.
