The way I figure, I think Nintendo should go for it and make Splatoon 2 a NX launch title. 

It should include all the content from Splatoon 1 (which shouldn't take long to port) and they can add on 6-7 new stages, 2-3 new modes, add a new quest in the single player, and then they can continue to add free content to it as time goes on. 

It's just too hot of a franchise especially in Japan and there will be plenty of people (hopefully) buying an NX who didn't have a Wii U, so you'll have all these people for whom this will be a new game essentially. 

Splatoon 2 + Legend of Zelda should ensure a good launch for the NX in fall 2016. Add in a tertiary title like a Diddy Kong Racing game from Retro or a Pikmin 4. Maybe an Amiibo Hub game. 

Then a new EAD Tokyo Mario platformer can come in comfortably post-launch to ensure there is no dreaded post-launch drought. Mario Maker 2.0 should be out early in the NX cycle too IMO. 

That'd be much too innovative for Nintendo.

Imho IF NX releases in Q4 2016 it'll be simply too soon to launch it, they would have to announce Spla2n in a few months by now... It's almost impossible to make an improved game in such little time...

I'd rather have Nintendo launch Splatoon 2 the second year of the NX, to keep the sales going and to work on tested internet servers.

I agree that it should be in paunch window, or at least in the first year.But if that were to happen NX would need to launch in 2017.What you are suggesting now is not Splatoon 2.Its the first one with some DLC, and that will leave a bad taste in people mouths.Launching late 2017/2018.Would be perfect, dince it would give time for the first one to get even more traction and more popular, and would give Nintendo time to make a true sequel.

Mario Kart should be a launch title imo.

I'd rather have splatoon 2 during holiday 2017. Would be a good system seller for the holidays.

If I had to guess, I'd say that a Splatoon sequel would come no earlier than 2017 (realistically 2018) since Nintendo likes to spread out its A-List franchises out over a five year window at around two per year (probably 3-4 a year if the NX really is going to have a unified library) and 2016 and 2017 is possibly going to be covered with a 3D Mario, a Zelda Wii-U port, Animal Crossing, Pokemon and Mario Kart.

Splatoon 2 could be a nice holiday 2017 title since I don't see Mario Kart or Smash come out in 2017. 3D Mario at launch in 2016 ( plus Zelda U and Pikmin 4) would be good enough.

I disagree, Splatoon is their shooter equivalent to MK and Smash so it has to be built on in the same way which means it can't be just rushed out for sales. I'd say 2018 would be a good time to aim for, NX will no doubt already have something for 2017 holiday. If NX shares a library between a portable and home variant then a triple attack of MK, Smash and Splatoon for 2019 may be the best call as it allows time to build on the previous games as well as give the NX a possible strong 3rd year and the combined output for portable and home console should already cover 2017 and 2018.