Thank you for the chest!
Regarding the Challenges, if there aren't any plans for sprinting, perhaps you could implement other ways to speed things up?
For example, special Speed buffs or buffs that increase the drop rate that activate after you reach a certain area.
Also, I really liked the Dungeon Points buff from last time. I wasn't able to complete the dungeon but it brought me a few levels closer than I ever could with the Dungeon Bonus alone.
You're welcome for the chest.
Special buffs for the challenge objectives sounds like fun, or maybe something like adapting those old speed buffs from some early event objectives (like Milk and Cookies) to work on challenges.
Yeah, the dungeon points bonus is a cool mechanic. There's a version of it available in the season pass purchase this time around.