Actually I think so, yes.

A) Yoshida keeps telling us they are still working on it (assuming he's not bullshiting) project was probably scrapped for PS3 and started over on PS4, probably sometime in 2011 or so, they didn't say anything since then cause the platform was the mystery, they already could reintroduce it last year, but maybe weren't ready yet. If there is time to proove that it exist, it's this year E3 or TGS.

B) Sony has shit line up this year, everything at E3 will be 2015/early 2015 (which could mean October 2015 in Soony language) so they need some bombs during the conference. Project Beast will be good no doubt, Uncharted as well but what else? Media Molecule's not attending, SSM just got a big project cancelled, doom and gloom, with pretty much GG and Bend left with games that can make some splash, but both studios have a lot to proove. I can't really imagine Sony having more big profile 3rd party exclusives alongside Project Beast.
That's where TLG comes in handy.

If they won't show it this year, I think the can as well announce it as cancelled cause I don't think anyone will believe it exists anymore.

Yes! It will happen!

Wasnt there a teaser at the ps4 launch event on how it is coming along and that it might have changed to ps4 instead?

I say no just to avoid any disappointment and maybe a happy surprise.

Well we can hope !

bend wont be there and ggs game may not be shown and is for next year

Ya, most likely

it all depends on MS conference how well they do..

This is such an overrated game which Sony will never release anymore, I am sorry but this last guardian thing has to stop!!! Sony should finally now care more about the people who bought a PS Vita because if I had bought a PS Vita I would be really disappointed by Sony and I still can't believe that no one is complaining about that!!! Everyone complains when a certain game is not 1080p and 60fps, i mean the world goes down when this happens, but when Sony not supporting their consoles and act like they don't know the people who bought a PS Vita then no one cares, its really funny :D

I really hope so. Fumito Ueda is one of the best minds in the industry, and I'm eager to see more of his work.

It would also give the PS4 line-up a nice shot in the arm.