I will add a poll once several replies are in, to have a better list instead of just the stuff that I can think of

Off the top of my head:

PSVR - there'll be a lot of eyes on this (as well as VR in general). For console gamers, this is the VR device that matters, I expect a lot of talk about it on gaming forums next year, and its sales will be intriguing to say the least

NX - Obvious..not much to say. This will probably win the poll, lol.

Uncharted 4 - In the midst of a lot of "franchise decline", how will this one stack up in the current market?

Gears of War 4 - same as U4.

What else?

PSVR and the NX (if it releases in 2016) are the obvious answers for hardware.

In terms of software Uncharted 4, Gears of War 4, Quantum Break and Horizon are the most interesting for me personally.

NX is a given.
I also think it will be cool to see how some of Xbox's exclusives like Quantum Break, Crackdown, Halo Wars 2, etc. do.

I think that is Horizon Zero Dawn vs ScaleBound, and Uncharted 4 VS Quantum Break.

lets see what Console will Lead in the Genres of Open World RPG, and Story Telling, Despite that i think that is unfair compare Horizon Zero Dawn, with Scalebound, because when it Release in the 4 Quarter of 2016 i think, there will Be over 50 Millions of Playstation 4, or even more.

But then we'd also have to consider some PS4 titles..and i'd rather not because I know they won't sell that much either ;( 

Poor Sony Japan Studios

Wii U:
- Pokken ( Lets see if Pokemon fans will support this one)
- Star fox ( gameplay > Graphics?)
- Zelda U (Everyone has been waiting for it)

3DS:
- Hyrule Legends (lets see if making a 3ds version was worth it)
- Fire Emblem Fates (Lets see if people like this new marketing or the whole 2 version thing)

Tbh everything you put in the OP (PSVR, NX, UC4, GoW4) will be quite interesting.

-To add to that I want to see how The Division does after it's huge initial buzz kind of fizzled.

-Final Fantasy XV: Will a mainline FF installment do well? Especially in Japan? How will it fare on X1? PC?

-ZeldaU: How will it stack up against other popular WiiU exclusives like Splatoon and Smash?

Uncharted 4 will be fine.

Gears 4 I expect to be significantly down on previous main entries.

I think what will be interesting hardware wise is seeing if next year will be the peak year of the gen for PS4, and what numbers NX pulls at launch.

PSVR, FFXV and P5.

Out of your list, PSVR. Will be interesting to see if its a flop of not.

In-terms of games, not really any that stand out to me