Soundwave on 30 June 2015
I don't think Nintendo really cares about "full third party support", in fact Iwata has even said they don't want full third party support (lol) when asked in the past.
I think Nintendo would be happy with basically what the Wii U was getting its first year plus the level of support the 3DS already gets from Japanese third parties.
Though I think Nintendo is worried about losing Japanese 3rd party portable developers to smartphones/tablets. That is a concern.
