Here's my tier list :
I don't like the "S+" tier and I don't think S tier should have more than 3 characters. So here's my reasoning for my list. The characters aren't arranged in a particular order
I used the best tournament variation for every character (or both if they are both viable)
S is reserved for characters with too many tools and/or overpowered tools.
Geras (both variations) has too many of them and are all good.
Erron Black has too many tools in 52 Kard Pickup. His Scud shot should be removed without nerfing it and replaced by another move. The Scud shot should be 2 slots and added in the third variation.
Sonya Blade (Ring Master) would be A+ with her damage, but her projectile is too powerful, and the Energy Ring cancel should not allow her to be safe on a mixup in the corner and at the same time allowing for a juggle in the corner. It's one of them, not both, so S tier.
A+ is reserved for very solid characters but not strong enough to be considered as the top 3.
Scorpion (both variations) and
Sub Zero (Dead of Winter) are both contenders for the S tier but there are stronger characters as listed above.
Cassie Cage (Digital Soldier) has a lot of useful tools and is dangerous anywhere in the neutral.
Baraka (both variations) is insanely good, has only a few tools but they are really really good, he would be in S in a heartbeat if the tier had available slots.
A is for characters I consider as "balanced", not too weak, but not too strong. Some of them are slightly stronger than other in that tier, like Cetrion, but didn't know who to swap in A+ to include her.
A- I usually don't like "-" version of tiers, but A- is a tier for characters that would fit into the A category if they didn't have whiff issues on most of their strings.
Johnny Cage,
Kung Lao and
Kano would be A to me if their hitboxes were good.
B - The B tier has the character with the least tools or at least unefficient tools at the moment. It has the weakest characters in the game.
C - I don't really know why I created that tier, I was probably influenced by other lists that rank her in her own tier. She is not far from the B tier tho.