I personally feel that this tier was missing from launch, its the tier that will keep the majority of players busy and coming back to the game.
Quote from another thead:
On the other hand if their goal is to create a tier that is based on difficulty to acquire, with:
Exotic(medium/casual) > Ascended (hard/dedicated) > Legendary (ridiculously hard/crazy dedicated),
then they are creating a system where the best stat gear in the game is hard to obtain and earned by dedicated players, which would go against their original Design Manifesto almost verbatim.
If this was in at the start of the game no one would moan, i think this extra tier is needed to fill the gap and keep more people happy.
these people: (hard/dedicated) are currently a little lost i feel, and need this middle tier between exotic and Legendary to keep them coming back and busy in the game.
this tier should have been in from launch its only an issue because it seems like the start of a tread mill when really its just filling a whole that was missing in the first place.
I dont see them adding any more tiers, i think this was a needed change.
just my opinion.