Nintendo will never get strong third party support and that is ok. With that in mind, Nintendo needs to do a better job of creating new IPs and taking control of some others that fit into their business model such as Mindcraft.
At this point I would drop the price of the Wii U low enough where it becomes "the other" console that every PS4 and XB1 wants to own.
Heck, if you want to really think out of the box make a deal with MS and create a XB1 and WiiU bundle.