It's universal, but the gaps are not. So based on which strings you can flawless block hits of, and how important those specific strings are to a particular character's meta, it could have pretty different effects depending on what the MU is.
If it's in a character's main safe midrange string, for example, that has to the potential to alter a MU a great deal.
You are assuming the low and mid tier characters have safe, mid-range strings to begin with. They are generally the characters with unsafe strings that have gaps. For example, Frost's b+2,2, Raiden's b+3,1, and Shao Kahn's f+3,4 have a gap between the first and second hit that is long enough to flawless block. On the other hand, Jacqui has a safe, 9 frame, mid-hitting, cancelable (with special moves as well as stance switch) normal attack that can be hit-confirmed into combos anywhere on the screen. If you gave Jacqui's f+3,1 to any of the currently perceived low tier characters, they would at least become mid tier characters.
I agree that 7:3 match ups are too early to call but the top tier characters are not. Historically speaking, NRS does not create deep fighting games. The characters that were winning in the second month of Mortal Kombat X as well as Injustice 2 would have been the characters that would have won forever if the games had not been patched. Believing that flawless blocking will all of a sudden catapult a character like D'Vorah to mid tier and allow her to compete with Geras and Erron Black is a delusion.
