I know Melee is a fighting game, I never said anything against that. I'm only saying your argument of how deep a block button can be holds no merit to MK because MK has no mechanics like that. It's simple block high or block low. The bare minimal. No push block, no parrying, no evade, no power shielding, no reflecting etc. I could never see Mortal Kombat doing any of those things (Forget Armageddon. Seriously? Air combat?) MK's blocking will likely always stay simple.
Parrying might work out, but more than likely NRS would make the window to parry too large like MK7 and it would be a combo starter. The perfect parry for MK would be like Wonder Woman's bracelet parry in Injustice.
That said, MK could never have back to block. Not with teleports like Smoke and Sektor's.