With current sales maybe there won't be a revised wii u, it may not warrant the investment. However which of the following features do you think is worth adding or changing to;

1. Top loading drive (like ps3 super slim, saves on manufacturing costs)

2. Gamecube compatibility (only really possible if it gets a top loading drive but shouldn't actually have much cost involved, all the hardware is already in the wii u except it would need some way of re-mapping controls to the gamepad. Practically a free option)

3. Usb 3.0 (will improve loading times)

4. Reduced size gamepad with smaller screen making it much closer in size and comfort to competitors controllers and with longer battery life.

5. Hard drive slot with fast sata connection.

6.  Reduced chip fabrication size.  Helps lower psu requirements, runs cooler and less noisy but requires some investment in re-designing the chips and might add to manufacturing costs depending on current rate for 32nm or 28nm fabrication.

7. Charge slot in top of console for gamepad. Just slots in.

8. Gamepad without screen but additional toggle button superimposes gamepad screen on main screen when needed with an analogue stick used to simulate touchscreen action.

9. Analogue triggers on gamepad

10. Independant Vibration feedback also added to gamepad triggers

11. Programmable resistance also added to gamepad triggers to better simulate weapon triggers and vehicle controls.

Software options;

1. Media centre functionality with wide range of codecs installed.

2. DVD playback

3. Enhanced game mode (all memory, gpu and cpu resources available in a game but console has to be rebooted after playing. This means a 100% boost in memory, an unknown increase in memory bandwidth and cpu performance.

I'd say #2, 3, and 4 for hardware. Then all 3 software options.

I would prefer the VC service to be improved personally.

the Wii at this point in its life had a stronger VC lineup

2, 4 and 9 preferably for hardware and all three software. Although I agree with PowerOfSoren that the VC needs a substantial boost. There's nothing more advanced than the SNES on it, which is a shame. I hope 2015 brings N64 and possibly GCN games.

I'd say of the options present in the original post, 1, 3, 4 and 9 would be great for revised Wii U.

Personally I like the size of the Gamepad but I get some people may not, so that combined with a lower costing device and a few better features given the state of technology today would probably lead to a few more people giving the Wii U a shot.