I might link some posts I made in the past — my ideas are largely unchanged — but what I think would make the most sense to please the most people (aside from my suggestions to make the mode as-is better, like seeing all draft choices at once) is basically a tiered option:
Tier 1: as is
Tier 2: Legendaries are now in the draft pool, troops are level 20, lower-rarity troops have traits
Tier 3: Mythics (and heroes?) are now available in the draft, and full stats of accounts apply, as with PVP
A person would have to choose his or her “Tier” each run in a manner similar to Explore (or, better yet, set it and forget it until the desire to change occurred), but then people would all get to play the mode how they want to. And that wouldn’t necessarily have to affect anything else, like reward structure 
EDIT for the linked thread; it’s still illustrative reading for anyone interested in the Arena, as very little has changed since these posts were written : Arena Worst Event Ever? - #27 by Magnusimus