Two reasons why:
1. Like a previous poster said, HHH coming back would have stolen Del Rio's thunder. Booker and Diesel were great additions, but no one realistically thought they were gonna win the Rumble. HHH however is a credible threat.
2. HHH logically needs to conclude his feud with Sheamus, so it makes more sense for him to come back at Elimination Chamber to screw Sheamus over, or debut the night after and challenge him at WM.
1. Like a previous poster said, HHH coming back would have stolen Del Rio's thunder. Booker and Diesel were great additions, but no one realistically thought they were gonna win the Rumble. HHH however is a credible threat.
2. HHH logically needs to conclude his feud with Sheamus, so it makes more sense for him to come back at Elimination Chamber to screw Sheamus over, or debut the night after and challenge him at WM.