The easiest way for me would be an exclusive sequel to Chrono Trigger/ Cross. This is the only sure gire way I would invest in another console at this time.

Wii U: Games, and I want to see how Nintendo reacts in the absence of third party support.

Xbox One: It needs things to differentiate itself from the PS4, and a game from Rare that I actually want to see.

PS4: PS Now not looking like a money vacuum.

Vita: Sony needs to actually let people know they still care about the damn thing. I also want to see better first party support and Sony not pushing it as a PS4 controller.

I have no time for more consoles anymore :-/

I used to buy them all as time went by, sometimes just to try 1 or 2 games on them, but getting older and having a house and kids make that time you have much more constrained...

Otherwise:

I may get a Wii U or Wii U like console when my first kid gets older, so she can play Nintendo games!

as for the XB1, I feel it's too much like a weak PS4... There really is not much point into getting it, unless some of the exclusives turn really interesting.

Ps4: Price and Games
Xb1; Price and games

Wii U and PS4: It's already pretty appealing actually I'm just poor

Xbox One: A massive revival from Rare

Xbone;
-Games
-Cheaper price

PS4;
-Games
-Cheaper price

BONUS;
Free online

Wii U : Cheaper.