3 Main event level guys vs Them in one cohesive unit. You want the first one on the booking / creative, and a business end. Those 3 have a past history with eachother and even interacting and pausing to smirk at one another after a few weeks of not being in the same segment / match gets a guaranteed fan reaction. There will be signs for ALL 3 of them at every RAW now. People are desensitized to Rollins vs Reigns, so now adding Ambrose to the mix helps you out a little bit to prolong that.
Eventually when that magic is gone, and the smoke is beginning to clear and the door to the enigma is running out of keys to try you'd best kick it down yourself. So here is where we're at now.
Strowman gets a monster push and it really doesn't have to derail Reigns. He pinned him after 2 spears and a whole lot more at the same PPV Owens got destroyed by Goldberg. Then every single week he's still been a pure monster. There have been plenty of situations like this where two people getting a push interact, and don't get derailed in the last 2/3 years.
Samoa Joe is on Raw, Owens is on Smackdown. I've not seen Jericho get a single legitimate "win" in against either of these. I don't picture him getting the title and going to Smackdown, then dropping it relatively fast. They're shooting the 2nd season to his web series, Fozzy has teased new music + touring, etc. near right after. There are really infinite scenarios when you have a guy who can flip an ambulance over, and the guy who just *retired* The Undertaker.
So Shield vs New Day. They're on Smackdown and Kofi had surgery and is still injured. It's been pushed and speculated Kofi would be pursuing singles competition or even gold. Considering Smackdown has MITB, and what not it's just not foreseeable. Different brand, Injury, Not having a lot of team momentum, etc. Wyatts are more than scattered, and honestly hardly even exist at this point. Bray already teased a feud with Balor, and after what I imagine would be Randy beating him 100% that's the follow up.
It's just not happening ANY time soon. 2018 I don't think it's too hard to see it, but as said 2017 is just not looking fit already in the first 1/4th of it for a Shield reunion. If it does happen it won't be anything long lasting or whatever. I imagine if they were going to pull it after next Mania and just run with it until it devolves into the Triple Threat Mania match people wanted for so long 2 years from now.