Yep, and while this might seem to contradict everything I've posted prior to this, there is nothing wrong with relying on past or returning stars if they're going to be working a program and not there solely for a cheap pop or so.
The problem is the method on which WWE is utilizing these past stars are mostly just short term profits rather than utilizing them to help solidify wrestlers as stars so that they won't lose as much viewers when Rock and crew take their leave of absence. Out of Brock, Rock, & Jericho, the only one who'll be working to elevate someone rather than face someone that doesn't need the rub is Jericho, who isn't on the level of drawing power as Lesnar/Rock. I still think Rock vs. Ziggler (though it's way too late now) could be amazing at Mania had the built it up right the months preceding, and as previously mentioned, Ryback/Brock could be very well and garner interest in my opinion. Yeah, it isn't the safest bet as the other alternatives but it could still be great and end up more profitable. Also, I'm not suggesting WWE should do both of those. They have two big stars, they could easily focus one for a pure dream match to fall back and take a "risk" with the other than what they're going for.
Finally, I feel the need to point out that people just want to see Rock & Brock in action, it doesn't necessarily have to be with one of the top guys like Cena & Trips. I mean, a big part of the audience Rock is bringing in are people who lost interest in the product for the last few years for whatever reason, a significant portion will actually clam Cena is the reason. So realistically, the portion of the audience is tuning in to see The Rock. They're not tuning in because John Cena is facing the Rock. They weren't tuning in because CM Punk was facing The Rock. They were tuning in, and the continue to tune in, because Rock is back and wrestling [on PPVs]. My point is that the people who are tuning in mainly because Rock is on, obviously doesn't rank Cena or Punk that high above someone like Ziggler because if they did they'd still be watching or won't stop when Rock goes. I'm not saying someone like Santino should be, but someone on the cusp of greatness like Ziggler would be ideal for Rock. And the same thing goes for Brock. People are tuning in because they want to see Brock. Those people aren't going to be turned off because you're pitting him against Ryback because they are mainly watching to see Lesnar.
Granted, they doesn't cover the entirety of the audience they pull in, but I still think it's worth bringing up.