Hello. Loving the game, played about 200+ hours so far. Finished Campaign, and done 187 expeditions. My suggestions for endgame are thus:

1. Ability to replay the Campaign Levels on progressively harder difficulties.

2. "Endless Dungeon" Basically an arena style round map where you fight wave after wave. Rewards based on Waves cleared. Alternatively this could be a really cool, "dungeon" where the floor is an arena and once cleared the gate opens and you keep descending downward. Every few levels, we could have a mini-boss or boss encounter.

3. Maze Level. Would be cool to have a puzzle level or a level where we have to run away from a boss chasing us while clearing through hordes of enemies. (Just a novel concept).

Misc suggestions:
Trophies or character flare. Think skulls on spikes or little trinkets we can have on our character. Warbanners, Capes, Cloaks,