Cygnuses are unavailable.

Yes because after, what, two years(?) we finally have some high level content again, that excuses EVERYTHING Nexon has done since practically Future Ereb was added. If you want to add Aswan to that, okay, but even Aswan and the Future were basically a year apart. Two sets of content for high level players in the last two to three years. Certainly some hard work there!

They went through the effort to make it easy to hit high level, but then they gave you no reason to want to be high level. There's a significant lack of content for high levels, and the little content we do have lasts a very short time in comparison to the amount of grinding you have to do after all the actual content is done. At 9-10 years old, there's absolutely no excuse for the game to be this devoid of high level content.

You forgot Magnus and Chaos Pink Bean. The bigger problem with their content is the accessibility of it. Bosses like Magnus and CPB (and later almost every boss after Unlimited) aren't accessible to regular players. What's the point of adding more content if it's not even going to be accessible to the vast majority of their player base?

Moreover my post was more about that "[high level] area that went along with the storyline that marks the buff for the Cygnus Knights." Not to mention all that's been revealed is Root Abyss and the buffing of Thunder Breakers in January and Wind Archers in February.

Even I believe Root Abyss will last for a short amount of time before we go back to Stronghold.

That's because it's not for training.