I found difficulty just right.
The most that bothered me is the long text for some actions...
Like, for the summon...instead of "you don't have this and that, and you can't do it", I'd just skip showing that option to the player.
It's best if you keep short text - one button tap, instead of two.
But it's just my opinion.
Perhaps in the end of a battle, a long summary would also be nice...
I really enjoyed what I played!