These kinds of games usually hold stuff back to release later on and keep the playerbase interested and spending money.
I wouldn't get too fed up over the lack of characters because they'll come, sooner or later.
Thoughts on the game itself, though, I like how they balanced no permadeath. Fits well with the small maps and no dodging. I can't imagine how hellish this game would be with permadeath on. Huh, maybe small maps + guaranteed hit rates would make for an interesting ragefest hack, now there's an idea.
Also yeah, raising unit rarity is expensive as hell compared to the amount of feathers the game gives you. I've gathered that we'll get feathers in the future from arena ranking, but just the cost from even just 2 to 3 stars is stupid when compared to similar games. It's a good thing my 5 star Hector and 4 star f!Corrin and Fir I got on my first pull have been carrying my ass so far.