One of the main reasons WWE are taking their time in announcing matches for WWE WrestleMania 28 is because WWE want to give time for The Rock vs. John Cena, Triple H vs. The Undertaker and CM Punk vs. Chris Jericho. WWE also have been considering leaving time for airing promos and vignettes involving the Rock.
According to PWInsider, the format of the show is still being processed, however it was mentioned last week that CM Punk vs. Chris Jericho would be opening the pay-per-view while Triple H vs. The Undertaker would fit in the middle of the event and The Rock vs. John Cena closing the show.
As previously noted, The Miz is not booked for any matches on the show so far. Miz is hyping via social media that he will be involved in the “main event” teasing his involvement in The Rock vs. John Cena match. There was talk of having someone involved in the match in order to set up the finish.