It would be reasonable to have them make F12 -4 on block instead of -3, most characters have the 9 frame down 1. Even though I'm pretty sure between D1 or D2 every character should already have a button 8 frames or lower to counterpoke/punish, but that will give people a bit more wiggle room. But it won't matter though, the bigger mind game is between ending at F12 or going into F12B2 and being about to react quick enough, or even the threat of armor.
Haven't messed with Displacer or MoS much yet to know what they need/if they need anything.