I think when it gets closer, they're just gonna go all Godzilla out on the I-Rex and just show the thing. The T-Rex we may see in the next trailer. But I have a feeling it's going to be very mysterious as to the circumstances we'll see her in.
This may already have been speculated, but I think that the T-Rex still exists within the old side of the island of Nublar where the first park was and has been surviving there. A place people overlooked or just neglected where the T-Rex has just been hiding all this time and has survived. And I think in the third act, Pratt, Howard and perhaps the kids get to that part of the island, a place that is completely unfamiliar to them, but familiar to us, and it becomes a battle of old vs new with the T-Rex squaring off against the I-Rex. It'll be the ultimate battle we always wanted, and it will more than make up for JP3 meaning that this time the T-Rex wins.
But I won't try to get my hopes up with this. I'm open to anything good.