I think there's very little that Nintendo needs to do to fix the WiiU. The pros and cons are listed, but update the OS to increase speed and release some games and there's little wrong with it then.

Dear god, just no. On screen notifications suck badly. I don't want anything to pop up while I'm playing a game. The current system is just fine. If anything important outside of your game happens the home button on your gamepad flashes blue.

pros
Its a Nintendo console, and plays Nintendo games
Best launch library ever
Gamepad itself is fantastic
Flawless,clever custom design
Surprisingly good internet browser

cons
Awfully timed marketing campaing
No flow of new games
Slow OS
Weak Wi-fi signal, it gets lost easily through walls

They can be optional like on the PS3, plus if they show up on the gamepad instead of the screen I don't see them being too obstructive. That flashing blue light notification isn't good enough. It flashes blue for every type of notification so you can't tell who just came online or if you recieved a message. At least on the 3DS those type of notifications are colour coordinated.

Yeah, it would have been better if they were color coded. But since the icon of the app also flashes and a pop up in the home menu...ok, I think I just found a good solution (at least for me): Instead of only having a pop up in the home menu when a friend goes online they should have a pop up for all notifications.

Example: Home button flashes. You press it -> Popup: KHlover has sent you a message on Miiverse/ KHlover has invited you to play XY...stuff like that.