The chat is either broken or the game is utterly empty so all 'social' elements of the game are dead and progress just drags that much harder for it.
League win advances you so much more than a loss sets you back that you have to forfeit or lose a half dozen matches just to get back into playable rankings.
Way too much OHKO with slim margins of health being the difference between having a living unit or a hole in your line while your fighters all level erratically and unevenly.
You rarely get the space to set up combinations since much of the game seems to revolve around losing an attrition by blows. [bards are the bane of fair play at my level]
There are hidden mechanics like 'soul bind' that force you to dig through every card you have to find them. Many things are not documented well within the game.
I still have no goddamn clue what gold dust does.
The starter event is both impossible for a new player and TIMED which is just a dick move all around.

Game has a lot of overlapping throttles to progress... cards, gold, gems, journey attempts, friendship points, timers. Underneath all that muck there's fun to be had! Shovels for 99$!