I'm not sure I follow, OP. Why should the changes to MNK, a perennially overlooked and previously largely unplayed class, be worrying to the rest of us?

Those who enjoy it will enjoy it, those who don't will move on. Not every job needs to be left with glaring problems that make it feel unfun, just to maintain some manufactured idea of identity. Similarly, not every job has become easier or had it's flaws removed or addressed, some (looking at you SMN) have become more complex and challenging than ever

So for those of us who haven't touched ShB MNK, like you and me OP, let's just let the many MNKs finally loving their class to do so. There's nothing to be concerned about with that.