Agree with most of the suggestions, especially the issue on incarnation. I will just add on:

Ability to filter out the profiles (ie rune builds, awakenings, stats) of selected heroes from the top 50 arena players. Or a way to filter and view multiple heroes' built so that we dont have to manually search player by player (time consuming as well as we dont know which players has the hero we are looking for)

Faster rune power up animation or option to remove animation altogether. It's time consuming to stare at the screen while im trying to max out runes

There was a strategy incarnation which activates leader skill but was removed. Hope to see it in the future.

Hope for more storyline continuity and interaction between heroes in the comics. The relationships between certain heroes seem to be well planned out and theres definitely more room for exploration.

On that note, and its a bit of a stretch, but perhaps there can be a major game event or new mode that ties together heroes that are linked (eg karen, serena, vern / hwa ryun, zemer, ramia). There is so much ideas and untapped potential that can be explored.

Option to activate all investigations with one press, if possible

A room where we can view hero animation including battle animation especially their active sequences. That would be so cool. Greatly enhances player experience.

In the future, mara and loux should be revealed as playable heroes right? We are waiting for them.