I know that it is uncommon for sales to go up YoY once they have already started to decline, especially in the 5th year but it's not completely unheard of. PS2 released in 2000, peaked in 2002 then sales started to slowly decline in 2003/2004. 2005 saw a YoY increase due to continued momentum caused by GTA: San Andreas and the PS2 Slim redesign in holiday 2004. Xbox 360 also had a similar occurence, it released in 2005 then saw yearly sales increase until 2008, sales in 2009 were down slightly then increased once again in 2010 due to the 360 S redesign in June followed by the Kinect in the holidays. So it can happen and one thing to note is that in both these examples, a redesign was a huge factor in increased sales, which by the way 3DS has coming next year with the New 3DS & New 3DS XL. Just for comparison sake, I will include NPD numbers for 3DS this year along with notable releases (games over 250k sold)
Jan-96k
Feb-153k (Bravely Default)
Mar-159k (Yoshi's New Island)
Apr-106k
May-96k (Kirby Triple Deluxe)
June-152k (Tomodachi Collection)
July-108k
Aug-91k
Sep-140k
Oct-138k (Super Smash Bros for 3DS)
Nov-515k (Pokemon Omega Ruby/Alpha Sapphire)
Dec-700-800k??? (Estimate)
Total- roughly 2.5 million
The first half of the year had a decent lineup, not great but not horrible, a JRPG, a couple B-tier Nintendo platformers and a surprise hit in Tomodachi, the problem was no real big system sellers in the first half. The summer was really bad, Smash Bros was delayed causing a drought and having zero big sellers release (it had a couple niche titles like Ace Attorney vs Professor Layton & Theatrythm: Curtain Call). The holiday quarter has been pretty decent, Smash Bros and Pokémon are 2 really big sellers along with a few smaller niche support titles like Fantasy Life & Persona Q.
Going into 2015, notable games we know that are releasing in the first half include Monster Hunter 4 Ultimate, Codename STEAM & Majora's Mask 3D so pretty much on par with 2014 first half releases. The big thing that I believe will improve sales is the New 3DS which I'm 99.99% sure will release in Q1 due to Nintendo wanting to hit their 12 million shipped total for the fiscal year. If it does in fact release in Feb/March then Q1 is pretty much gauranteed to by up YoY. The second quarter could be up as well if it has a prolonged impact on sales along with Majora's Mask releasing. Going into the summer, the New 3DS boost will probably start to level off and it comes down to if Nintendo has any significant titles releasing unlike 2014. I could see games like Xenoblade Chronicles and Youkai Watch releasing in Q3. Xenoblade probably won't be huge but if Youkai Watch has anywhere close to the success it does in Japan then it could really help Q3 sales. The holiday quarter is where I don't really see sales being up. The big holiday title will probably be Pokemon again, I'm guessing an enhancement/sequel to X/Y (Z, X2/Y2, XZ/YZ) alongside some smaller support titles or localizations (Final Fantasy Explorers, a B-tier 1st party title). They can probably keep the decline to a minimum tho by offering some nice New 3DS discounts/bundles for the holidays.
Overall I would give it a 50/50 chance of being up YoY in USA if the things I outlined above happen.
When the herd loses its way, the shepard must kill the bull that leads them astray.











