Just saw this update on the PlayStation Blog..
"As you know, Naughty Dog is wrapping up production on Uncharted 4: A Thief’s End with the game on track to go gold and into production later this month. In an effort to meet the considerable worldwide demand, and to ensure that all gamers worldwide have the opportunity to play the game on day one, we have chosen to postpone the launch of the game by two weeks to allow for extra manufacturing time.
Therefore, Uncharted 4: A Thief’s End has a new worldwide release date of May 10, 2016.
We know this news might be disappointing, and we are sorry to have to make you wait a little longer to play Naughty Dog’s latest. The good news is that the game is phenomenal — we are fully confident that it will be worth the wait and the team at Naughty Dog is eager as ever for you to experience Nathan Drake’s final adventure.
We thank you for your continued support for PlayStation."
Looks like pre-orders must have exceeded expectations.. I'm disappointed in the delay but oh well.. at least it's only for 2 weeks more..