We all know what is happening at Mania.
Cody will defeat Roman. The Bloodline will try to get involved but Jey Uso and Sami Zayn will arrive to fight them off, and Cody beats Roman clean. I assume Roman leaves for several months after that.
The other main event is almost assuredly Punk winning the Elimination Chamber and challening Rollins for the title. I doubt he wins it, though. I don't know that WWE wants to put the title on Punk, nor do I think Punk wants to be in a position where he carries the major title again.
What that means for guys like Gunther, McIntyre, Knight, Orton, and Styles? No clue.
I think we are moving towards Styles/Knight based on their Smackdown interactions and their Rumble fighting. Knight probably goes over.
I think Mania is just gonna be super "meh" this year.