Terumi just needs to repeatedly hit microdas 5B which is +2 on block and that's infinite pressure as long as you have your microdash link timing down. As for mixup, he has an overhead special now so that's what you wanna go for. Messenga doesn't really need to be invuln since he also has soutenjin, they just wanted him to not get a full combo off of an invincible move so they made it like carnage scissors. 4D is a combo filler basically yeah, as for 6C, nobody good ought to be getting hit by that raw. Doing raw 6C is only worthwhile when you rc it (after they obviously block it) and go for a mixup off of the rc, it's not a thing you throw out and hope it actually hits, if anything I'd take that as a sign of disrespect and promptly fatal your ass, since it's just that punishable on block XD. If you wanna punish something as idiotic as Susanoou hitting 4D in front of you, just 6B fatal into OD into 6B>charged CT>full combo...and I kinda don't even wanna comment at Naoto just charging his guard crush in neutral in a predictable fashion lmao.
Oh and messenga never was close to being the best super in the game, if you wanna look at back in the olden times, black hole literally made Kokonoe boardelrine broken lol. It was just your average invincible super. Also, don't forget in CF we got exceed accels, they want us to use them so they took out invuln off of a lot of things like houtenjin and whatnot, though houtenjin always would die to meaty grabs anyways.