I don't think the Wii U will find any huge success to be honest just because I don't think the concept itself is all that appealing to people who are non-Nintendo and that's not going to change with price cuts.
They do help of course, the GameCube got a boost from its price cuts, but price reductions generally don't bring on board people who don't like a console's concept or it's general style of library.
I do think a price cut would help the Wii U in the sense that to be honest a lot of hardcore Nintendo fans also tend to be a bit on the cheap side. They're not used to paying a high price on hardware, so a lot of them are staying on the sidelines. You'll see it on this very board, a lot of the most ardent Wii U supporters don't even have the system themselves, lol, so if Nintendo is having trouble getting even those people on board, then obviously price is one part of the problem.
The people who aren't into buying a console just for Nintendo IP and don't see a Wii Sports/Wiimote type hook for the Wii U this time around aren't going to bite at most any price though. They all already have PS3s/360s that have better software libraries than the Wii U and if they are going to upgrade the natural step up from that is PS4/XB1, not Wii U.
So in that case it's pretty much screwed, much like the GameCube, a lot of people refused to buy it at any price, because why pay even $50 for a GameCube when you're perfectly happy with your Playstation 2? You can use that $50 to buy a game. That's what happened with the GCN and I think Wii U is pretty much on the same path.