Their idea behind Stormblood was that you should be able to play any role job without too much consequence.
They also said they wanted to decrease the difference between "casual" players and "elite" players.
I don't see much of this actually implemented with Stormblood at all.
And MNK is like the 2nd best DPS after Samurai, your proposed changes would make them more powerful as a consequence. Monks don't need more power.