I grind the arena a bit and I'm often shooting for that 1-5% reward range to get the 5,000 5* shards + 1000 6* shards. In this recent basic DDHK arena, I scored about 25mil points and got rank #329. I'm mean I guess that is cool but I already have DDHK as a 5* and sig 40, so this just added 1 sig. 1 sig vs 5k 5* shards is a pretty big difference in rewards for the time put in and I ranked higher than expected/wanted and got 'less' for it.
The idea I would like to suggest is that the #101 - 500 rewards be a 2 choice selector instead:
Option 1: 5* Arena champ + 1,000 6* shards
Option 2: 5,000 5* shards + 1,000 6* shards

Thanks for you consideration.