I think it would be very nice to show the previous heroes/gauntlet used to clear a floor of the Onslaught/DOD, if the player cleared that floor previously. I have included a crude mockup of what this could look like.
When I first started the game and was barely clearing the dungeon, I took a screenshot of what heroes I used and was switching between the photos app and Knighthood to select the same heroes since I didn't remember all the combinations I had used to win. Now I am a higher level and can farm the normal Onslaught dungeon but it would be very convenient to press 1 button to use the same heroes as yesterday rather than scroll through my heroes 2 times per floor.