Yeah, Y/Y decline seems like a given overall. But in terms of stemming, I imagine the expectation/intent/hope of the n3DS is to either stabilize sales next year and/or to even reverse the trend.
Probably boils down to, put simplistically:
Upgrade Buyers - |Decrease in New Buyers| > 0
Considering they won't launch the n3DS in most of the Western markets this year, I'd agree we probably won't see a new handheld launch next year, so 2016 is the next most likely candidate I guess.
I think it could work in Japan, but I don't really see it managing to stem declines in the US/West; so I don't really know if waiting until 2016 to launch a new handheld globally is the best idea.
Consumers are more used to half-step rapid upgrade cycles though.
I suspect at some point they determined they couldn't be ready in 2015 and decided on this instead.
If we assume a Fall 2016 launch, they also have an incredibly full plate even now:
1.) They have an impressively large (for one company) line-up of Wii U games in development or recently finished, and these are the most resource demanding games they've ever created.
2.) They have promised they're working on am array of 3DS software including N3DS exclusive software, which also require a fair amount of resources.
3.) Someone has to be working on whatever QoL is.
4.) Even if we assume Fall 2016 for the next handheld, if they want 2 year dev cycles, a bunch of people have to be working on them now, and they're likely to be notably high resource games if they want to take advantage of their own hardware.
This is actually an angle that helps me explain why I've been pessimistic that Nintendo will go full bore on absolutely everything.
While Nintendo is growing, this would be notably more demanding than they've ever been able to meet before. It's possible they're able to handle all of this at sufficient volume, as their new office is quite big on top of their new publisher team up push, but historically speaking it wouldn't be unreasonable to suspect at least something to get less support in favor of ramping up on others.
I mean, as an honest question, and even if we ignore QoL, do people expect them to handle all three game items there on full blast? Maybe someone who follows Nintendo's resources closer than me can tell, but I guess this is also what drives some of my assumptions that they're going to pick two of the three as the big focus for the next two years.
They could turn down Wii U support after 2015, they could make a light effort on the 3DS's latter years, they could hope third parties are enough to launch the 4DS, they could delay the 4DS past 2016, or they could have hired 1000 new developers over the past two years without me noticing (do they list game specific R&D staff somewhere?).
This is not to imply a unique Nintendo problem once again. Sony dropped internal Vita support in favor of the PS4 and Microsoft had very little late gen Xbox 360 support and almost no Windows Phone (or even Windows) support in favor of Xbox One. Apple and Google don't even release games.
And finally, obviously being pessimistic about all of these fronts would be silly, and it would likely be unfair to be pessimistic about more than one given Nintendo's size and history.
Now, admittedly I feel I've been pessimistic about both 3DS late gen first party output and 4DS (I'd consider light first party support and a 2017 launch equally bad), but that's because I can't tell which of the two they're actually working on and feel their E3 announcements showed a very strong commitment to the Wii U that I didn't assume prior. Their statements imply strong 3DS support upcoming, but their lack of announcements does not, so I've waffled between whether they're going all in on 4DS or just haven't announced their strong 3DS position yet.
Again, in theory they could be handling all three well, it's just that I haven't seen specific stats (that could well publicly exist, and please do share if you know them I would be more than happy to eat crow here) suggesting this is likely the case.
But yeah, basically I see the pressure from their own commitment to the Wii U, the desire to capitalize on the 3DS's success, and the desire to move on from the 3DS before they have massive harm to the product line (especially in the West) as notably competing and that historically the company has not shown an incredible ability to juggle all of that simultaneously, leading to some of their current troubles.
We've seen Sony already completely fail on this front via the Vita abroad and the PS4 in Japan, and Microsoft's Windows and Windows Phone gaming efforts would be hard to explain as anything but failures.
I do think if they were to cut somewhere, the 3DS is the one that would suffer least for lack of strong support, given how much it's already sold and how far it is into its lifecycle. It's also the platform I feel they have lots of guaranteed support on even with my concerns about shrinking mid-tier support across the board for dedicated devices. Final Fantasy Explorers is a good example of a game that's chasing the high end created by Monster Hunter despite Square Enix's general skittishness, and obviously we've had phenomenal success for Level 5 in chasing the audience Pokemon carved out, so those are encouraging signs for getting third party investment targeted at big sales even at this phase.