A) Games: Yes, the main reason. It's not that there aren't games to play on the console - and good ones at that. It's that there is not much that distinguishes the WiiU as its own experience compared to the competition, and certainly not for being the most expensive as well. Along with heavy hitters like Mario Kart, Nintendo just needs more exclusive games even if they're not system sellers by themselves (Pikmin, W101, X, Bayonetta 2, Wind Waker, etc), and they need something that really proves the Gamepad as a game changer.
B) Price: Somewhat, yes, but sub $200 is certainly not necessary at this point in its life if the game situation was rectified. $249/$299 would suffice.
C) Power: No, other than it could limit 3rd party support once the new consoles are out. The mass consumer doesn't care as much about a big leap in power as the enthusiasts would like to believe... especially if they have to pay a premium for it.
D) Gamepad: No. I've said it before and I'll reiterate it again - the Gamepad will be what saves and differentiates WiiU. Again, Nintendo needs the right games to showcase it; something much more than Nintendoland. And for those who want the option of pro controllers or Wii remotes for more mainstream games, they have them.
E) Lack of Focus: Yes, at the moment. I do believe that being able to satisfy everyone is great but Nintendo currently isn't doing a good job of it.
F) Marketing: Definitely. It sucks. Period.
G) Apple, etc: No, other than everything does compete for people's leisure time, but if Nintendo creates the experiences people want to play they will come. This comes down to games once again.