[Hiero_Glyph]

Would it be possible to rework the existing maps/game modes to offer an endless mode? This would add more content without requiring new campaigns. It would also give players a way to grind out objectives against increasingly difficult enemies.

Potentially, increasing rewards could be used but if you fail before completing the current objective you would lose everything. This would offer a high risk, high reward scenario.

Cycling maps/objectives and rewards could be used to keep things fresh and prevent grinding a specific combination. There are more specifics that would need to be worked out but this is the general idea. Let me know what you think.

[Angeles2099]

I like that idea, Warframe has things like that where enemies come in waves of increasing difficulty and they give you the choice if you want to leave your team and take what you've earned. 
It would be cool if they had that and every time a player leaves you gain extra loot on top of the bonus you get for higher difficulty waves.