He's not fizzling any time soon... he is simmering nicely and the Rock interaction was a major coup... BUT
Don't for a SECOND think it's cos he is "thought highly of"...
It was a purely political move... they had just had the flag stuff so this week they give Rusev something pretty "substantial"...it's not rocket science, the company is getting heat for Big Show dropping a flag so they make Rusev the focal point as a "make up". They also drop the Rock's theme 3 or 4 minutes before the hour, so Twitter etc goes nuts and people change the channel... so this episode will have a massive ratings spike. Pretty smart on WWE's part considering the Kathy Lee stuff tanked.
BUT
The segment was vintage Rock, he could have shown up and phoned in a segment (or even done the satellite thing) but he clearly put some work into it both live and before hand, he put Lana over and make Rusev look a credible threat...who someone of his level would a) be aware of and b) think important enough to want to interrupt... of course he "handed his candy ass" to him but he's THE FRICKING ROCK!
In terms of exposure, it puts Rusev into that upper midcard territory/main event level rather than with the other recent debuts... even Bo is moving into the IC picture now but Rusev has bypassed that now, even the supposed US title feud with Sheamus... now he's facing bigger fish.
What this showed was that Rusev and Lana are ready to step it up a notch in who they face AND think about it... Survivor Series is next month, traditionally that is a PPV that Dwayne likes to work... he can run a tag match and get the same payday.
I can very easily see a 5 on 5 Team Bring It vs Team Rusev scenario developing. Rusev, The Dusts, Cesaro and Luke Harper vs Rock, The Usos, Sheamus and ostensibly Big Show... heels take out Big Show and the mystery partner.... Kurt Angle... It would also deflect if Brock isn't present. a 5 on 5 scenario protects Dwayne and allows Rusev a "defeat" to someone of the Rock or Angles level, but with reduced damage to him... Being eliminated in Survivor Series doesn't damage someone as much as one on one...and if he loses that pin to the Rock, then he's covered...
Even if they don't do this route, it showed that they could trust Rusev and Lana with someone like a Kurt return and make it work.
Lana deserved a lot of credit in that segment too, she handled it well, didn't fluff her lines and gave the right air of disrespect to the Rock to make the beating he took all the better.