Forgive my snark (although I do find it humorous the point is somewhat moot now that the content has been re-removed).
My frustration wasn't, and isn't, the content itself. My frustration was (and continues to be) that PD is well documented as having an extremely small set of dev.s. This means that any specialized content (a la the BMW Japan promotional or the recent Red Bull top gamer Japan competition) is taking developer attention (that could be spent developing content for everybody) and focusing it on creating content that only a small subset of Gran Turismo players can use. This means that things like the BMW Japan promotion or the Red Bull gamer challenge only happen at the expense of content that was planned for everybody else (such as this long-rumored/planned mountain track in Spain).
I don't have a problem with PD working with other companies for promotional materials, but if they want to do that, they also need to make sure that they are still able to fulfill their promises to the rest of us (the promises that led many of us to purchase a game that, even at the time of purchase, felt clearly unfinished). If they want to pursue special relationships with other companies, that's cool, but our money was good, too. Now that we've all spent it, though, it feels like they don't care about the money they took, only what money they can get next (from sponsors and special corporate partners). Unfortunately that is leaving the rest of the Gran Turismo community (the community that got those sponsors and corporate partners interested in the first place) out in the cold.
I quite agree that the special-color M4 isn't a huge deal. I also agree that not getting to play certain seasonal events isn't a huge deal. I also agree that a little bit of lateness on the delivery of content like this track in Spain isn't a big deal. Put them all together, though, and it's kind of a big deal.