For the last two days in Las Vegas, Big 12 Media Days took place at Allegiant Stadium. With four new teams – and two departures – the conference bag its new era with a bang. But in a conference room across town, another media event was taking place with the league that used to play its title games in that building. The Pac-12 gathered for its annual media day, dubbed “After Hours with the Beavs and Cougs” this year, to debut a new look in more ways than one. Just two schools remain in the conference with Oregon State and Washington State left behind after a groundbreaking round of conference r…