I'm not going to read through all the other posts, so I apologise for repeats, but here are my 2 cents:
*Should have provided devs kits earlier
*Should have made it easy to port 360 games by providing a framework to do so
*Should have courted the 3rd parties by doing the above, but also showing how cheap it would be to develop compared to next-gen
*Should have got Minecraft signed up 2 years before WiiU launch
*Should have advertised the system as brand new, not an add-on, took them over a year to realise the confusion
*Should have streamlined the interface before launch, not 2 years after
*Should have given it a better name, a name that infers it's new, HD and different
*Should have advertised it to consumers
*Should have followed through with Nintendo TVii, and in all regions, it was a good idea but they gave up
*Should have made it region free
*Should have had the full VC library form the Wii available to launch (full conversions I mean)
*Should have priced it at $350 with a game, then brought it down to $299 with a game a year later
*Should have had MK8 at launch or soon after
*Should have scrapped or reworked NintendoLand into something worthwhile and understandable to all
*Should have launched with small Amiibo range and a game, then expanded them to Smash at a later date