A lot of people have noticed that FFXIV took a classic vertical progression system, which has been confirmed with Heavensward. This system comes with its count of problems, which are the following (non exhaustive list):
- More levels mean more new skills, half of them being irrelevant in 90% of the situations, cluttering the skill bars
- More levels make previous content less and less relevant
- More levels means that players interrested in end level content end up rushing the leveling phase, passing the cutscenes, forcing people to pass cutscenes in story dungeons, ... and thus lowering the interrest in the storyline
- More levels means that lower level experience requirement gets nerfed, it takes less time to do level 1 to 60 than it took to do level 1 to 50 in 2.0, which is kind of a nonsense to me, what is the point of adding more levels if it doesn't extend the play time.

There are more, but you see my point.