No, there's a difference between how the Wii/GC and WiiU/Wii BC operate. The Wii's CPU and GPU are literally just overclocked versions of the same components in the Gamecube, so when the Wii is playing GC games, all it has to do is clock down the CPU and GPU by one third and it basically just becomes a Gamecube, and hence experiences the same frame drops and performance issues.
The Wii U is a different thing altogether. Even though the CPU is reportedly based on the Wii's Broadway, just clocking down to 729MHz and running the code on one of the cores won't result in identical performance, as the significantly increased cache and possible microarchitectural changes could certainly affect how well CPU-limited games run.
The GPU is a bigger issue, as the Wii U's GPU is of a completely different architecture to the Wii's. I think this quote from the Wii U Iwata Asks is relevant:
(He's talking about IBM and/or AMD designers here)
I take this to mean that the Wii U's GPU doesn't have TEV hardware, but is configured to run Wii's graphics code natively (or easily emulate the Wii's GPU). Once you're running code on hardware it's not written for, it's very likely that performance won't be 100% identical to the original hardware. Given Nintendo's attitude on VC games, I would fully expect them to err on the side of improved performance.
Long story short, it's quite possible that the Wii U could play Wii games at improved framerates, but I wouldn't expect any major difference.
Even software emulators (which the Wii U will almost certainly not be) have to run at the speed as the original game, or it'll break the emulation. You can run the game faster, but you can't speed up the actual processing. Like, if a game is slowing down during a certain scene, and you speed up the emulation to get it back to 30 fps, the game will be going 2x the original speed at 30 fps, not 1x at 30 fps, if that makes any sense.
I think you can overclock a SuperFX chip and get Star Fox running slightly faster, but there's no magical, 'now it runs at a decent framerate' fix for anything that's being emulated. It's not like a PC game where throwing better clock speeds gives improved framerates without touching the game's overall speed.
I say that there's almost no way that Nintendo is doing software emulation of the Wii because that wouldn't guarantee 100% compatibility, even the Wii's VC games are relatively untouched (no 16:9 fix or filtering), and those have to be software emulated.