A Few Suggestions I Find Helpful and The Developer Might Consider
1. In the Level Up, add "Select All ISO-8"
2. Sort champs in the champs page by rating in Default
3. In the Arena, add "Ask for Help for All"
4. In the Leaderboard, add Alliance ranking filtered by region, for the reason that it will helper players to search for the strong alliance in the region as timezone is a factor when comes to which alliance to join
5. In the Leaderboard in general, when click into an account/alliance profile, then click [go back], it would go straight back to homepage instead of the Leaderboard, which makes profile checking inconvenient.
6. In the top tiers AW, a lot of times alliances on both side are equally strong and they can both 100% all 3 battlegroups. The win, in that case, often comes down to a few more diversity and/or defender kills. I personally feel in those cases both alliances have made similar efforts and the difference in determining win/loss is tiny. It is unconvincing for one side to loss the war just because 1-2 diversity/defender kill.
The goal of my suggestion is to make war harder to that a proportion of top alliances can't clear all battlegrounds so that the difference between win and loss will be clearer. There are probably a lot of ways to make it harder like beef up the nodes etc. And I'd like to suggest to make the miniboss and/or boss partially/fully hidden in the top few tiers. If players can't see what character are placed in miniboss and boss, or can only see their rating/class, they'd have no idea what champs to bring, which will make the war unpredictable yet fun. And in that way top tier players would not need to worry about not to die, since some more alliance can't finish all battlegroups and defender kills wouldn't matter that much.
Thank you for your consideration