There's a few threads on it from yesterday still hanging around: https://www.reddit.com/r/Guildwars2/comments/ae0m9t/mike_z_is_it_reply_to_the_redbull_article/

I wouldn't worry about it, it's a pretty standard PR response to say: "We're going to make the content as best as it can be". Saying expansion-level content is just saying the content won't be like S1-3 and instead follows a more grandiose story telling (The last few were always a bit fragmented or smaller).

Ie. No one expected to fight Balthazar (rightly so at the time, biggest fight was Lazarus) in LS3, and no one expected we'd go actually go up against Kralk either but they delivered on it.

That being said, it's not a terrible thing if they cut up an expansion put inside patches instead, it simply means we get better and more polished content over time instead of one big drop and a bunch of smaller/mediocre stuff after.