The "fix" has, at best, only moved the problem and me up one tier but the basic problem still remains, the low tiers are clogged with mostly fully tricked out legendary and epic defence teams that should not be in these low tiers. I'm a new player (2 months old) just in Bronze 2, I go up to just under the threshold for Bronze 3 but fall back overnight rdy for a repeat the next day, if I could sit and refresh every 12 min or if I had an endless supply of crystals it might be possible but I have other things to do. The Arena problem also means I'm still stuck on the Progress Mission stage that requires you to get to Silver 1. 

Suggestions (Pointless I know, do Dev's ever come here and read?)...

Maybe tier restrictions for Defence Teams i.e. Bronze Tiers = Rare Champions only, Silver Tiers = Any team with one or more Epic Champions but no Legendary Champs, Gold Tiers = Any team with one or more Legendary Champions.

To add your  Defence Team to the combat listing for that day you have to fight the 5 Classic Arena matches from the Daily Quests, if they aren't completed then your Defence Team doesn't fight for that day.

Remove all Arena missions from Progress Missions as the Arena is currently a blocker on any progress with these.