I have been running a lot of arcade recently, and it always saddens me because you reach the end of an arcade so quickly. It's a lot of fun exploring all the different levels, and I am constantly finding scenarios I have not seen before. I would like the depths in arcade to get extended. By the time you start making 1kcr+ per level played(unless you're finding a lot of arenas) the arcade is already over.
Proposition:
Have emberlight begin at depth 21, so that tier 2 goes from 9-20. This change will make elite orb grinding much easier for newer players.
Have tier 3 go from depth 18-35. Tier 3 will be 7 depths longer. Depth 28 is when you start making big bucks. This will also make radiant grinding a bit easier. Depth 35 will be the depth Shadow Lairs take place at. Having a 100% chance for crates to drop gold crowns and a extremely high radiant fire crystals chance.
All missions will still be the same depths and reward tiers. There won't be any change in how much loot you're getting in your boss missions.