The Wii U is in a tough situation right now, and most would agree that it's a lack of quality games currently available. While I'd say this is definitely true, if the Wii demonstrated anything it's that a system can be made compelling out of the box. By contrast, when I bought an Xbox 360 years back, it was to play other games than what came in the box (Marvel Ultimate Alliance).

The question, then, is if you'd been given the choice, what changes would have made the Wii U more appealing in-box? Assuming the same games available at launch, and the same level of marketing, would you have cut the power to offer it at a lower price, or increased the power and sold it at a higher price? Ditch the GamePad, make it optional, or double-down with an even better screen? Change the design of the casing, or the controller, the box, or even the name?

Or if you think the console itself is fine, would you have changed the SKU's? Different games bundled-in, or other models besides the Basic and Deluxe?

Drop the price by $50, bundle with SM3DWorld instead. Make this the basic bundle.
Include a WiiU pro controller and 64GB HDD instead of 32GB into above bundle and sell it as the new premium bundle.

EDIT: Oh, with games aviable at launch? Simply cut the price by $50, 32GB as baseline internal memory. White Premium Pack.

Make 32 GB standard, include $350 and $400 models with a game and up to 500 GB of storage.

I'd announce more than one new game at the first E3 after the system releases.

I counted more than one...

I would make sure that Super Mario World 3D, Smash Bros Wii U, and Mario Kart 8 were launch titles.

$ 300 - White/Black with 32 GB bundled with NSMB U or NL with every service and update now availabe already installed on launch.

Different name
Cheaper
Packed in pro controller
Built in replacable HDD
Mario game bundled

#1: Get rid of that stupid, awkward, clunky tablet controller. This alone would also solve several other problems with the system...

#2: Make it more powerful. Now that there's no expensive tablet required, we can spend a bit more on the inner workings of the console so that it's not a generation behind again.

#3: Design the system so that it doesn't look EXACTLY LIKE THE WII. This will also help to clear up the confusion that still persists among general consumers and casuals who aren't sure if the "Wii U" is just a peripheral for the Wii or not.

#4: Launch the system with games that don't look like Wii games in HD. It's REALLY hard trying to sell a new console to serious gamers when you're charging more money than current gen consoles, and the games you're launching with look WORSE than on current gen consoles.

#5: Change the name. Words cannot describe how stupid the "Wii U" name is, how it sounds, and why anyone thought this was a brilliant idea is still a mystery.

Do all those things, launch the console at $299, give it an online infrastructure that doesn't suck and also doesn't feel like its a generation (or two) behind, and for God sakes give the damn thing more internal storage than what a typical $10 USB thumb drive has these days.

The problem is that doesn't really make the system more appealing, in and of itself. I think most people would agree that more games would make the system sell better, but it'd be because of the games, not the system.