While I don't expect FFXIV to take center-stage, it needs to be at E3. To not show the recent changes and planned changes would be an economic suicide just as bad as the way they launched the game in the first place.

From a sales and subscription perspective, what is currently hurting FFXIV the most is the people who walked away 6 months ago. You have here a collection of players who rage quit (and I really mean "rage") when the game was at its worst and have since been advocating that people not touch this game with a 2000 foot pole. I'll quote a friend of mine who is among these people:
"FFXIV is currently nothing more than the framework of a mediocre MMO. Square Enix would be better off cutting their losses and scrapping the game entirely and then using the engine to re-make FFXI or some other game."
And people take him seriously since he is top of his class in Australia's leading Video Games educational institute.

These people of course know nothing about what has happened since Yoshi-P took the reigns, making their comments to people considering picking up and trying out FFXIV exceptionally uninformed and unhelpful. These are the people that Squeenix needs to, at the very least, silence from their bad press, even if they can't get them playing again. And they can't do this in the game or it's community itself - they can only do this in an environment that is attentively watched by gamers and press across the world that would otherwise attempt to avoid news on this topic.

E3 & TGS.

These events give Squeenix a rare opportunity to actually tell the quitters how things are changing and show that, come PS3 release, the game is actually worthy of consideration in a second round of reviews. They would be very foolish to not take this opportunity.