I know nothing about MK X as I've never enjoyed Mortal Kombat so I can't offer any contribution to that aspect of the discussion.
IN MK:X, you are given 3 different variants of each character.
FOr example, sub zero gets ice weapons in one, ice clones he can throw in another, and enhanced ice projectiles in another.
Only a few moves change, but it changes a matchup entirely because now your options are completely different.
However, just because there are more options doesn't inherently give it more depth. GaW has a custom special where his hammer is always either a 9 or a 1 (iirc). That's not deep. That's just silly. I'm sure not every custom move is as extreme as this, but there's going to be a fair amount of testing involved to determine if having the custom option available is worthwhile.
Actually it is, because now you need to deal with a GnW who can possibly homerun bat you with a side B.
What do you do? you approach him more safely, or you may play a bit more risky because of the changes to his abilities.
The depth doesn't come from the move itself, that is a shallow method of viewing it, the depth comes from the options that they provide and how the opponent must now deal with it.
In anycase, i found a video with the whole custom moveset list I'll post it here.
Custom moves
Anyone too lazy
Neutral B: Same as we know it.
Neutral B #2: fires straight down.
Neutral B #3: Anti-air ariant of the homing attack
Side B: Same we know it.
Side B #2: Has a pop. Landing on someone with the pop slams them into the ground.
Side B #3: You're on FIYAH! Removes the pop, has a slightly higher hitstun
Down B: Regular
DOwn B #2: Multihitting variant, seems to do more damage?
down B #3: Vortex while charging.
Up B: Regular spring
Up B #2: Double spring
Up b #3: You get a hitbox during the spring jump, rather than only being able to hit with the spring.
That would be it.
Neutral B #2: Seems useless? not sure, might bounce straight up with no recovery time maybe?