Well, of course. It's never a bad idea to keep increasing the number of devs!

I would say they need more western developers to help with sales overseas and possibly new IPs.

I think in a unified platform structure (NX) they should be able to manage 12-15 full-blown retail titles every year no problem.

You actually don't want too many Nintendo games because then they start to cannibalize each other in sales.

I'd say increase Retro so that they can comfortably work on 2 games at once, and open another 200 developer Western studio.

Again if you combined their 3DS + Wii U output for the year you'd get a library that looks something like this:

Zelda: Majora's Mask 3D
Codename: S.T.E.A.M.
Fire Emblem Fates
Animal Crossing (lets just mix HHD and Amiibo Party)
Zelda Triforce Heroes
Xenoblade X
Splatoon
Mario Maker
Yoshi's Wooly World
Mario Tennis Ultra Smash
Star Fox Zero
Devil's Third

That's two Zelda games, a large scale RPG, new installements in several Nintendo franchises, a new major Nintendo spin-off (Mario Maker), and three new IPs (Splatoon, DT, and Codename: STEAM). 

I'm even excluding things that might be redundant in such a lineup like the Xenoblade port for N3DS (though that would mean Monster could've made a different game) and leaving out games like Fatal Frame that shipped the year before in EU/Japan.

But that's a lot of Nintendo games to be honest. If you have more than that you're probably getting into the realm of overkill.

Yes, they need to make more games to make up for the lack of third party support. If the NX has a similar amount of support as the Wii U then it will fail as well.

Hiring more and more third Party collaborations would be great

Yes, they do. And the first team they should buy is Platinum Games.

I once saw an interview that took place in the Nintendo of Italy's headquarters and the buildng was HUGE, even tough there was near to 0 employees in the building and it was spring when the interview was made, clearly there are expenses to do when there are more employees, but I'm shure it's better to pay those expenses thinking of a future return instead of just paying taxes on the building in countries like mine without any sort of internal developed game... I'm shure Nintendo of Italy isn't the only one with plenty of space for new devs, as well as I'm shure that there are enough good devs out there that would love to work for Nintendo with a resonable revenue, all of us are well aware of the fact that Nintendo is keeping hiring people, but some of us as you can see from the poll think they should hire more people than they actualy do

They should hire Kojima

They should hire Phil Spencer.

I don't think it's just number of developers they need to increase, it's diversity as well. For every Tangled, Frozen and (insert title here) Pixar movie, they need Pirates of Caribbean, Marvel and Star Wars movie...so to speak in Disney terms.