The Live Letters preview everything that will be added in the given patch cycle. The next one will outline what is coming directly in 7.2, what will be in 7.25, etc.

This is their design for releasing content and has always been their design for releasing content. You seem to be fairly new by your join date. If you're comparing this game to other MMOs, don't. While it has some inspirations, it doesn't follow all the trends of other MMOs. Instead, do a little research on the game first and see what individual design it follows.