I haven't tested on everyone, but I couldn't find any character-specific stuff here until now.
Yeah, I think it's a really good tool post-GB at tip range. It deals (almost) as much damage as 66BB CE, but only with one BE, and it gives RO and W! as you mentioned.
So post GB we have:
8B+K ~ BT B+K ~ 33BB = 69-71dmg ---> 0 BE, no RO or wallsplat
1A ~ AA BE ~ 3B ~ 3B+K = 97dmg (at close range after a handful of moves, but never on the Pyrrha's, Leixia, Viola, Hilde, Algol and Alpha) ---> 1 BE, possibility for RO forward and wallsplat
8B+K ~ G ~ AA BE ~ 3B ~ 3B+K = 100dmg (at tip range) ---> 1 BE, possibilty for RO backward and wallsplat
44[A] ~ AA BE ~ 3B ~ 3B+K = 100dmg (after 44K, 1B+K, WS K) ---> 1 BE, possibility for RO forward and wallsplat
66BB ~ CE = 101dmg ---> 2 BEs, no RO or wallsplat, but works at every range against everyone
And some wall combos post-GB:
1A ~ AA BE ~ 3B ~ W! ~ 4A+B ~ W! ~ 6BA ~ 6BA/6KK = 149dmg (170dmg with CE at the end)
44[A] ~ AA BE ~ 3B ~ W! ~ 4A+B ~ W! ~ 6BA ~ 6BA/6KK = 153dmg (174dmg with CE at the end)
8B+K ~ G ~ AA BE ~ 3B ~ W! ~ 4A+B ~ W! ~ 6BA ~ 6BA/6KK = 158dmg (179dmg with CE at the end)
Without CE, they all require 1 BE.
In my opinion, if there is no wall nearby and you don't know if 44[A] or 1A ~ AA BE will hit your opponent, go for safe 101dmg with 66BB CE.
If you know something else will connect or you have a wall behind your opponent or yourself, try to go for a wall combo.