I don't think you can take Trott away from No.3, he's there to add security to the top order so that the opening pair can go and express themselves a bit and then Trott can come in and pick up the pieces if need be. With Strauss + an aggressive player opening, runs are going to come quickly however if someone goes early then he can come in and steady the ship and then pick up the scoring. If Strauss and Trott opened then it could be a little slow to start with and then you're not making the most of the hard ball at the start of the innings and then leaves too much to do down the order.