To be fair, metrics are far from the issue when it comes to WoW's many problems.
Blizzard is effectively the hostage of Activision, arguably the most profit hungry company in the entire gaming industry. I doubt Activision cares one bit about WoW's internal metrics or long-term planning or vision; they only see the immediate profits and how to create systems that force players to play for longer to squeeze sub money from them in the short term. Ion is just a yes-man for Activision at this point. Speaking from my own time working in the game industry, publishers alone can be the most annoying force to deal with when it comes to creative decisions. Let alone a publisher like EA/Activision that is insanely profit hungry to the point of sticking the metaphorical middle finger to the gamer's face because they know the playerbase will still eat up the big franchises they put out.
Compared to Yoshi-P who isn't beholden to some higher up publisher, and was even promoted to the lead of creative business unit III, showing that his fellow leads on the board have much respect for him. That being said, FF14 already has its long-term plan and vision. 6-7 years of consistent design in how certain types of content are tuned is a really hard statistic to ignore; FF14 has been advertising the demographics each form of content they create is aimed at for a long time now. Every piece of content in the game has its purpose and will not be deviating from said purpose this late into the life cycle of the game.
Rather than wasting time asking Yoshi-P for harder 4 man dungeons which have been so rock solidly integrated into the design of this game as the easy, spammable daily task, people should be asking him for more unique 4 man content like PoTD. I think asking for more unique 4 man content will go much further in their feedback than asking for harder dungeons, which I can pretty much guarantee any feedback of such is likely just auto-deleted by their sorting AI program.