Worrying about what happens to hypothethical new players when they want to pick up a hypothetical new expansion seems like a waste of time.
To the bolded part, this attitude is entirely at odds with the development teams attitude for the game. The older content isnt "useless" its simply what came before, its no more or less "relevant" than the new content. You are also completely wrong about it being a different storyline it is a direct sequel to the storyline that ran through 2.0-2.55, as in a day or two later direct. Could they have "solved" this "problem"? Sure, but they clearly dont view it as a problem. People are carrying on like they're being forced to read one book in order to read a new unrelated one thats just been released when in reality they're being asked to read book one in a (currently) two book series.
Being asked and being forced are not the same thing.
If they asked, they would have solved this problem by telling us we can "read" ours journal instead.
If we are looking this from a gaming perspective and stop using analogy about reading book, a lot of games allow you to skip part 1 and just play their brand new game instead.
You don't need to play TW1, or TW2 to enjoy the TW3 and vice versa. Even though the lore, story and world are connected, they didn't force or block you.
If we are talking MMO such as WoW which is also story heavy, they re-summarized a lot of past contents for you and actually "ask" and give you a choice if you want to relive old contents or not.
And if we still want to use book analogy, nothing can stop you from reading the sequel. You can throw part 1 in the garbage, and start with part 2 and read a summary somewhere instead and enjoy it day 1.
You can be a fan afterward and decided to go back and read part 1...or drop the whole book series and watch the TV adaption instead.