but also abyssea is essentially: hey! we're gonna incrase the cap to 90! everyone 75, come here now!
a day later, you're no longer 75 you're 90. now where is the game inbetween this? why not increase the level cap to 9999, and just get you there in an afternoon? where is the actual game content from level 75 to 90? does it actually exist or is it just a gimmick? allow me to use spinal tap as an analogy:
The idea was to lower the demands of large groups, since the game is nearing the age when people will start dropping off. This could of course have been solved by lowering all HNM levels by 20, but SE decided it would be more fun to add levels to the players. Same deal really.
I.e. same content, but less demanding of having 18 people camp your HNM. Luckily SE didn't stop there and make us all camp Fafnir in groups of 3 people, but added new sources of armor as well.
The levels are just numbers. What you should be looking at is the game play, and how people play now compared to before.