And yet they chose not to, hmm go figure, eh? I don't know why you wrote overhauls as "overhauls" because even though english is my 2nd language, even I know that overhaul means a revision, sometimes large revision of a system which they're doing now. Also no, they knew well before the game launched it wasn't in a suitable state hence why they said to hold off reviewing it while they finished ironing out the issues.
Saying that they purposefully released a poorly optimized game, especially compared to their last 2 MMOs, would be like saying the alpha version of the game was the version they planned to release but knew that people wouldn't accept a "half assed game" so they created the beta version.
Considering I've played both of their MMOs, XIV was majorly rushed in all definitions of rushed release. Since we're throwing the "their own words" around, just before open beta XIV was still "For sure in 2010, but no exact date", then all of a sudden, right during a crucial time and financial period given little coming out of SE's studios for 2010 and early 2011, XIV has a release date?
The quote you listed further proves that they didn't have "5 years" of working on XIV. You know what else proves it? 2007-2009 FFXI update cycle and update quality. WoTG took 3 years to complete because 2007-2009 pulled the team to work on getting XIV ready for testing, XIV is released, look at the updates XI started to receive. So again, if the game was released in better quality, we wouldn't have had to wait, but now that we have to wait for them to overhaul, yes overhaul there's no escaping this fact, the game you can bet it would have been implemented by now since what would they be able to focus on instead of having to retrace steps? A transportation system is in no way the same work load as recreating a foundational system such as the battle system which they have to now in order to begin doing other work because thats clearly how bad the game is in on the back end.