If those mb b3/ mbf3 launch for +30% combos, allow to blowup most gaps, can be used as antiairs and can be thrown in the neutral, these are the main reasons why they got witch hunted in mkx, and removed in consequence.
These ones, on the top of that, have more range and are safe or plus on block.
And "they are slow" is not a good point, slow armors didn't survive October patch either. Only a few select one got the privilege to become two bar launchers.
I give props to op for bringing this subject to the table, nobody talked about this before. The fact that people were used to these moves in inj1 doesn't make less incoherent to defend them after what happened in mkx.