The overall agreement seems to be that JC is big, but far from unmanageable
The downside is that it does very little to affect the board
Still, accepting that players like them, they do make your deck slightly more efficient (the focus here being on slightly )
Stanng, Echo Warrior propagates the Voltron pile youve assembled every time you attack, which is kinda awesome (though it does limit you to non-legendary Auras and Equipments, for the most part)
Kaito enters attacking the same player, planeswalker, or battle the returned creature was attacking
Abeyance as it was originally printed prevented your opponent from tapping lands for mana