Personally, I don't see any point in them doing so at this point.  Typically, a new coaster announcement would be to draw people in, and I think the fact that park is opening at all (and is basically the first park in SoCal to open, aside from Legoland), is enough of a draw right now.  Save the announcement for later, once more time has gone by.
Franky, who cares if people see construction for a new ride?  People saw Nintendo construction way before Universal said a thing about it. They were just like, "Construction? What construction?":whistle:For that matter, they haven't said a thing about HHN, either, even though it's pretty obvious two mazes are at least partially up.