For my part -
1) Ennis is an interesting player to watch. Interesting insofar as he's always on the move (except in his d-zone where he either a. he has been the first forward back and is commonly falling over himself in a defensive panic, or b., is otherwise standing around looking uncomfortable while waiting for someone else to figure out how to get the puck moving in the other direction), and throwing his heart into the game.
2) Ennis is like every other guy will show the odd flash of a Crosby or Ovechkin move, but who really doesn't have the soft hands, the cycler's mentality, the snipper's shot or the power-forward's body to drive thru. He's interesting, shifty, and good for tight-in solo plays where the combo of his heart and his wrist shot work for him, but he's just not got extra-special quality that makes him a top 6 lock on any given roster.
3) Ennis' defensive game remains much the same as it was when he was playing center - it's subpar at best. He's for sure not the backchecking floater of Moulson's style thankfully, but I think Nolan did Ennis a disservice not keeping him on PK duty this season to refine his comfort in his own zone. Sabres could have dealt with a few extra short-handed goals to give Ennis that development opportunity. So, staying on wing seems to be his future, especially given the depth.
4) The bulk of his offensive wows seem to come from solo plays (see #1 re: always on the move and throwing his heart all in) rather than from chemical play with others (ie: give 'n go rushes, sustained o-zone cycling, etc.), so it'll be interesting to see how things unravel when the roster flushes out with a stronger top 6 of guys who are playing more than a dump 'n chase style of "offense".
5) The fact that Ennis' even-strength production numbers per 60 minutes have actually stayed the same from last season to this one raises more questions than it suggests he has merely "improved"...
a. relative to last year, he's had the benefit of playing with the best producing guys the roster has to offer so you'd expect his production to increase accordingly, but it actually hasn't.
b. offset a. with how he's arguably been playing against better quality opposing players yet still managed to produce the same numbers at even strength.
c. put a. and b. into context with the fact that he's produced the same numbers over a year of playing with multiple linemates, which at the very least suggests he doesn't need to rely on any one guy (ie: Moulson) to produce (it'd be interesting to see how his numbers break down according to who he has been playing with though...?)
d. if he's returned to the 2nd line, it's reasonable to expect that his production for the season will stay much the same as it has the last two seasons - this based on the notion that he sustains the same per 60 minute production but sees fewer minutes per game than this season
e. if he sticks to the 1st line, it's reasonable to expect that his production for the season will improve - this based on the notion that having Kane and Eitchel/McDavid for linemates will be an upgrade over Moulson/Stewart and Girgensens/Larsson, etc. and he'll likely see much the same minutes per game as this season
6) The fact that Ennis' biggie "improved production" is actually sourced to nearly doubling his power-play per 60 minutes production over last season suggests a few things too...
a. if he sticks to the 1st unit power play next season he'll likely see much the same numbers - if not even better re: quality of roster improving around him
b. if he's shifted to the 2nd unit power play next season, it'd be unreasonable to expect his overall numbers to stay the same as this year because he just won't have the same opportunity
All in, I think he's interesting and hope he's not traded (well, unless it's part of something way bigger of course;-)). He strikes me as one of the heart 'n soul types who will continue to have his slug/cool stretches but always turn up again to snag that timely clincher from shear will alone.
But to be fair to him and expectations of him, with the way the roster looks to be flushing out going forward, I think those of you looking for Ennis to be a locked-in top 6 who generates 60+ points are in for disappointment. He's 40-50 pts on a bad team in large part because he's been one of very few options for every opportunity possible. Even if you offset his lowered ice-time on a different roster with the fact he'd likely be up against weaker opponents, you're still only looking at a 20+ goal scorer maxing out at 40-50 points depending upon quality of linemates, etc.
That's not a bad thing, 40-50 pts is great for a 2nd/3rd line guy and Ennis has shown he can be consistently in that range regardless of the circumstances. But expecting 35+goals and double that on assists is arguably unrealistic.