I'd go with Bryan challenging Lesnar. I'd also use Rock with somebody current rather than HHH getting the one-on-one match that he never got at Mania. He'll, even Rock vs. Rusev with the spark already having been ignited would interest me more. Sting vs. HHH assuming Taker is out. Do Cena vs. Reigns if you like, face vs. face.
WWE World Heavyweight Championship
Brock Lesnar (w/ Paul Heyman) (c) vs. Daniel Bryan (RR Winner)
Icon vs. Authority
Sting vs. HHH
Face of the Company (on a pole
)
John Cena vs. Roman Reigns
Bring It to Lana's Putin
The Rock vs. Rusev (w/ Lana)
Money In The Bank Briefcase Ladder Match
Dean Ambrose vs. Seth Rollins
Winner Takes All: Intercontinetal Champion vs. United States Champion
Loads of guys you could use here, let's say; Barrett (IC Champ) vs. Sheamus (US Champ)
Not a unification match as such, just an opportunity to make the belts worth something and put a shine on someone at the top of the midcard.
Divas Championship Match
Clusterfuck.
31 Man Tag Team Battle Royal for the WWE World Tag Team Championships
15 teams duke it out for the gold, add Big Show/Henry/Kane as a lone man, or have one team have 3 members.
Not sure what you do with Orton.