Thanks for your hospitality,
I should have stated in my description that I also do not believe the rock to be back live in even a part time roll, I'd just like a few satellite shoots after the challenge, with most of the mic work coming from Heyman. Hopefully if "best for business" is truly Vince's mantra he would find a way to make one match work in Rockys busy schedule.
However, I can see your angle from the Orton POV. Personally I haven't been interested in Orton in years, but his title reigns speak for themselves. Maybe a 3 month "vacation" offscreen can bring back some interest. I just feel like in order for the title to go undefended for 4 months and not have a riot, the feud needs to be booked soon, at least hinted towards, and whomever the challenger is their focus needs to be only on that match. No other feuds from now until Rumble. Anticipation and believability if you will.
I wouldn't object to it but I think people would dislike the idea of no Rock or Lesnar..speaking of which, Heyman wasn't on Raw?
I do agree the challenger should only care about the match with Lesnar and no one aside from Cena right now cares all that much about the title at all. So your idea of the Rock works really well.
That's the problem with this title reign right now. Believability and who cares about it. Right now the only believable opponents are: Cena, Orton, Triple H, Bryan(debatable but still) and people who haven't wrestled in a while(Rock, Taker[maybe]).
Now who cares about the belt...Cena
Orton shouldn't care nor should Trips because they both support Lesnar as champ. Bryan is injured. Unless the Rock makes some claim about it then it's just Cena and Bryan.
But to defend your point, doesn't Vince apparently want a Brock/Rock match at Mania? So I could see the WWE doing it.
As far as Orton needing interest, if you meant for you personally I agree. He's got very little to accomplish. But it isn't needed, he got a decent pop when he came out tonight. Could you imagine if next week Cena is getting a beat down by Rollins when Ambrose comes out attacking the Authority. Orton rolls out of the ring comes back in with a chair and everyone assumes he's going to go after Ambrose or Cena but he bashes Rollins in the skull(well he'd do the back but still). Fans would lose their mind cheering for him. I think the problem is the fans would turn on him so fast though. If anything I think his match would have to happen within a month or two after his turn. Too long and the fans will be booing him, sort of like what they do to Cena.
They could do both. Remember a few years back, when Rock returned and became number 1 contender at the Rumble just because he's the Rock. So here's my fantasy booking to make both occur.
Next week, like you said Rock says he was returning to challenge Brock but he never showed up and he went after Rusev because he couldn't deal with the bad mouthing of his country. Then Orton turns on the Authority the way I suggested earlier in this post. He grabs a mic and says he's done being Rollins and Triple H's lapdog. He says he was promised a shot at the belt so he's going to use it at Survivor Series.
You book Orton as the inbetweener here. He can insult Rock, but he's still going after Lesnar like a good face should and he'll even come to the aid of Cena/Ambrose. Basically xD to simplify.
Orton's Rivals: Lesnar, Rock, Authority. In that order. He's mostly a face but we need to believe he'd fight Rock at Rumble if he wins the belt. Meanwhile, like you suggested Rock has a promo every week or other week talking about whupping Lesnar's candy ass at Royal Rumble. They set up Lesnar v Orton at Surivor Series.
When Orton loses(because let's be serious he will) you can keep him as a face basically by kissing up to Rock and helping out Cena and Ambrose. All the while, Rock/Brock keeps getting built up. You can even have Cena getting mad because he deserves a fair rematch.
At the Rumble have the Rock lose. Now if Reigns wins the Rumble, we can have Rock sail off into the sunset. But if anyone else does. They can build up a Rock/Reigns match at Mania. Orton and Rollins feud will conclude at Mania.
Basically, Mania 31
Bryan v Lesnar(c) = Bryan
Rock v Reigns = Reigns
Orton v Rollins = Rollins
Dean v Triple H = Dean
Of course it'll never work like that xD plus it's way too many new guys winning. But that's how I'd like to see it go down to include both ideas