The notion of something being rushed would imply that there was some kind of attainable and intended target for which sacrifices in quality were made to reach that target by some deadline. It would be something like saying you were going to develop five new armor sets and do so, but two of the sets are mere reskins of existing armors because you lacked the time to model more than three new sets. Saying you were going to develop five new armor sets and instead only producing one and calling it a day is not you being rushed. It's a gross overestimation of what you are capable and willing to deliver. Selling products based on this overestimation of future delivery is borderline criminal. If ANet managed to put out a full set of legendary weapons, but several of them had "lame effects", low quality textures, poor modelling (clipping), buggy acquisition, or similarity in design (akin to Sunrise & Twilight), then calling that rushed would be appropriate. The reality is much different.
You could make the case that ANet didn't want to sacrifice quality on the legendary weapons and thus decided to only put out four relatively good ones rather than about a dozen-and-a-half rushed ones, but you still wouldn't call this rushed and it still wouldn't be anywhere close to the original selling point.
This excuse has worn out its welcome. People said the same thing about the base game when it came out and would still say the same thing about it today, but they're wrong. That's okay for ANet though, because there are still enough deep-pocketed morons in the GW2 community who will pay based on promises of product rather than product itself. God forbid consumers learn their lesson.
As pointed out, this does raise the questions of why this had to be done, incorrect focus/priority/timescales and the like? I hope it is simply the developers being more thorough, however the recent patches and previous legendary collections do not help this view. Perhaps someone has given Mike some information about what people like to do, and what they are most interested in. I'm in the more story content camp, rather than 12 more extra shiny skins.
TLDR; I hope it's just Mike doing some prioritizing and I support the shift, but I think the problem is likely to be an issue with timescales and manpower in dev corner.
True enough on the bit about what the playerbase wants. I definitely get the feeling that people sticking around with this game are far more interested in the products of ANet's writing department over anything else. Playing through story missions sounds much more appealing than grinding out thousands of materials for a skin. That being said, the reception I've heard about HoT's story was that it was rushed (or what they really mean is that it was bad), and the reception of the living story chapters leading up to the expansion's announcement was mixed at best, so I don't really understand why people are really looking forward to that either. Also, new story missions alone won't really sell an expansion. To just put those out would harken to the release of season two that was free for anyone who logged in for two weeks from release and had a cost for anyone coming on later. That will probably be limited to the people now who own HoT, or maybe not, and will probably still require you log in during the two weeks after release, or maybe not. Who knows really, ANet just changes their minds all the time about what kind of convention they're going to release content under. Only having new story missions and free admission (if you log in at the right times) to future story missions does not bring the term "expansion" to mind. For that, you need to tag on other projects you promise you'll get to in the future, like real underwater combat.