They are being purposely hyperbolic. Tripling the content as you purposed would better pace people's activities. Yes, I can have everything done in a day or two, but it retains greater longevity because I have additional options. Three dungeons means Expert Roulette has six potential options, three 24-mans keeps each fresh for longer. Now I certainly don't anticipate them ever being able to afford the immense cost and development time for such a task. It does, however, make things feel... emptier. I'm still taking the "wait and see" approach with Eureka and PotD 2.0. If neither prove interesting...
The issue becomes as FFXIV ages, new players replacing veterans will decline. Many players posting do not even take umbrage with occasional lulls, but the current patch offers very little long term content. There's a stark difference between demanding a constant flow of new content and expecting things to last throughout a patch cycle. Right now, the devs are clinging to Ultimate, Ivalice and PvP to hold player attention for fourteen additional weeks. Ultimate appeals to a small portion of the playerbase while PvP has been notoriously underpopulated-- made only worse by piss poor moderation and adjustments that have rendered it a bot riddled mess. On the subject of swimming, people aren't upset with its inclusion, but the fact nothing has been done with it. They sold swimming as a feature and it's little more than aesthetic. I like it for the same reasons you do, however I had hoped they might expand on it further. And no, that does not mean Blitzball.
Put another way, a friend of mine has repeated groaned they've spent so much time on Squadron AI and Perform. Why couldn't those be used for actual content? I can't exactly blame her either, especially seeing just how complex the Squadron stuff looks. Personally, I don't see running around with three bots as "new" and "innovative," even if it does have potential.