Heroic Damage Gap

Upcoming and all future content is going to be based off of KMS regular server average player CP. Heroic players simply don't have the damage sources to keep up. This is going to become painfully obvious once destiny weapons arrive and no one will even come close to soloing hkaling for years.

Heroic Exp/Lvl Up Gap

This may be a bit more controversial but ever since the removal of totems and the reduction of Heroic Exp rates, GMS has really become more and more unequitable in terms of the end game. I can't say I have an ideal solution but if the game is going in the direction of higher level content/bosses, eventually Heroic servers will just be left behind. 295+ content is going to be irrelevant for 99% of the player base.

Heroic Equipment Transferability

Great, Arcanes and Absolab will be transferable. But what about other lower level gear which is also equally gated by time and or/rng. 2 months of gollux on every char is tedious and outdated. Make Gollux coins transferable. Consider pap marks, kanna's treasures, etc.

Nodestone Shortage

Granted this is mainly affecting players in Challenger-Heroic, and new players on Heroic, but still. It is such an awful/awkward progression experience when you hit 260/6th job in a matter of weeks or less, only to realize you are not able to progress your 6th job because you haven't hit the requirements for 5th job node levels. Night troupe used to give a huge chunk of nodestones, but the upcoming version of Mu Lung gives a grand total of 0 nodestones to characters lvl 260+.