As long as there is a way for me to somehow spend the ingame currencies on skins I want, then the grind isn't that much of an annoyance to me.
All is random, so no, you can't spend in-game currency for the skins you want. You'll spend for a chance to drop the specific gear you want. No more ''ok, Cassie's alt oufit is in that box, gonna grind 20k coins and I'll buy it.'' You can literally play hundreds of hours without unlocking the specific gear you want. Plus, seems Towers of Time are hella difficult. Borderline impossible, and that gives you more coins. Maybe they'll patch the difficulty, maybe not. Or you can spend real money, don't know if you can buy the specific gear or more coins.
It's clear all they want is your money, that's why they never talked about the Krypt before.
It's Injustice 2 2.0. Welcome to the new Era of Mortal Kombat guys, have fun.