I have Dallas as the highest change in points. With Radulov, Hanzal, Methot, and Bishop they should be way better than last year. Honourable mention is Tampa Bay.

I might be forgetting someone but right now i'll go with Arizona.

Dallas...by a wide margin over ARI

Arizona and Dallas are good picks, however just based on the anomaly of a season they had, Colorado.
They finished worse than the McEichel Sabers who sold on top of selling. The team was not built to suck so bad. Duchene is probably going to have a better year and probably eclipse his usual 55+ points. Landenskog will probably reach 50 points. Rantanen will be a little older with some NHL experience to help him grow. Erik Johnson was hurt for part of the season. Zadorov was pretty decent at shot suppression. Barrie had a terrible shooting percentage last year and it will probably have a better offensive year. Also they have some decent to good prospects in JT Compher and Tyson Jost.
They aren't going to good maybe .500 give or take but not the .293 that they were last year.

Dallas, I have them finishing second in the central division.

Sabres