I decided I'd buy White 2 after how much I enjoyed playing Pokemon Y. Gen 5 is the only Gen I never played or had interest in.
I & II were outstanding, I liked III but it felt sort of empty after the Regis/Lati@s
Between Diamond and Platinum I racked up a great deal of hours, I enjoyed it even though it wasn't as memorable (which I feel had to do with age)
Obviously HG/SS and then the hiatus of BW/BW2

What should I expect/look for in W2? Or what mindset should I have?

Also, have you ever skipped a Generation that you were cynical of just to come back and give it a fair chance?