Isn't FoE for soloing, like Titan-egi, and not really meant to be useful in group content? And FoW is just for running around when not doing instances, just to get around faster. Not all skills have to be useful in all contexts. Just about every class has skills that aren't that useful 99% of the time in a PvE raid, trial, or dungeon setting. I mean, when's the last time you've seen Freeze used outside of PvP, or Sneak Attack in a 50+ dungeon/raid/trial, or Tri-bind, or the binding ninjitsu, or stone I when stone II is available, and the list goes on... useful skills in the right situations, sure, but those are few and far apart, and it doesn't break those classes to have rarely used skills.

Is MNK broken in some way? Is there some issue with the class that you think needs to be resolved? If so, then changing underused skills to correct that issue makes sense. If not, then why change those skills? If the class is balanced without the changes, then giving skills a buff means giving others a debuff to maintain balance. If there's a balance issue you're seeing, that's another story.