I suspect PS3 support will be dropped around the release of the second expansion. They have already committed to supporting 3.0 (expansion 1) and it wouldn't make a lot of sense for them to suddenly drop support in the middle, so I don't think we'll see PS3 support dropped or phased out until at least 4.0.

That being said, the people saying that the PS3 isn't holding the game back at all are delusional. It's incredibly impressive to see what the team has done under the extreme technical limitations they're working under (eight year old hardware with one sixteenth the amount of general purpose RAM of a low-end laptop or PC manufactured in the past few years) but there are limits to what they can do, and until they decide to phase out support for the PS3, every single new feature or system they seek to add to the game has to be specifically designed around "how can we make this work on the PS3." The memory budget for just the user interface is so strict that the team cannot even afford to display the Focus Target UI without disabling a few other UI elements. What if they want to add other persistent UI elements as part of a future expansion or patch feature? I'm sure they've left a little bit of space in the memory budget for future features but what happens when they run out of even that?

Yoshi-P has wisely decided to not hold the game to supporting the PS3 forever, because he knows that to do so would hold the game back in the long run. And MMO development is all about "the long run". At the same time, support for the PS3 won't be going anywhere anytime soon, and you can be sure that when they make the decision to drop it they'll let the playerbase know *far* in advance.