Character Depth
I feel like you guys can improve on making each and every character more unique. Some or many characters even share the same voices out of unknown reasons. Please try to give every character a personality. Maybe even add something like Character Quest for each individual character. Showing how the main characters interact with this particular unit you just summoned, or got through quests as "quest drop". You could take a look at a game called "Granblue Fantasy", how they handle the particular Character Stories. And maybe completing could give us rewards in form of...Gold or Gems whatever...maybe even weapons who knows

I am sure many players would enjoy this kinda thing...getting to know the character better. Seeing him/her as a buddy; Having sympathy for him/her; Thinking of this unit as husbando/waifu because of their unique and special personalities.
Like for example let's say, Kai on the outside is pretty cool and calm but when it comes to food (chicken) he can't hold himself and goes nuts. The truth is, he likes food above everything in the world. I wish that you guys could look more into this. Making the stories actually enjoyable to read. And if we reach a certain number of units (male and female). You guys could make contests, socializing with the players or competitions on "Who is the most beautiful?" (where players can vote for their favourite units) Something sorta like this. And yeah, it could open much more new events where certain units do something together and encountered this and that (Man i suck at explaining, hope you guys understand what i am trying to say).
Fact is, the characters should have deeper personalities -> Players sympathize with 'em -> Have more fun getting the units/playing with these units/discussing with others why he or she
is the funniest/most pervert ( ͡° ͜ʖ ͡°) /husbando-/waifu material ( ͡° ͜ʖ ͡°) -> Opens new possibilities for community loved and ingame events.
Tho these are all things which take time but i think it would be worth also focusing on this topic - Unique Characters - that is.
As of now, collecting these characters don't mean that much to me. They just have nice art, that's all. Add personalities and different high quality voices and you should be good to go for the future. For now i am just hearing two same voices the whole time, it gets boring

Friend List
As of now it only shows their Level, Lead and Relationship. I would prefer when "Last time active" gets added to this. Maybe even something like "Status" but the later one is just...if you got nothing to do

Guild
Can't scroll down the Location thingie. In my case it is set on "Singapore", but i want to somewhat change it to "Global", since we want to accept people from all nationalities as long as they can write english a lil bit. But well,can't scroll it for now. Cant Change the Location. Please fix it

Also maybe a feature to look up other guilds when you are in one guild already, would be nice.
That's it for now. Every other complex ingame feature is discussed in other threads already (Faith System etc.) I will just edit it, once i find more things to write on

May this game get popular and beat Summoner's War out of the charts. Cheers.