Sabres fan here, chiming in. Surprised only a couple other Sabres fans have chimed in with only a few things.
The positives: Skinner can still snipe. He's absolutely lethal in close and in the slot. His shot isn't hard, but it's accurate....he won't be hitting 85+, but he'll put it exactly where he wants it, anytime. His edgework and close-range quickness is/are still elite. When he's on his game, he's a yapper that does not shut up (ever) and will get under the skin of opponents. He will occasionally battle along the boards, and is usually pretty good at puck control. He has underrated vision and is a pretty solid-to-good passer. While he's not a "leader" per se.....he's a great character to have in the room. Go look up "Between Two Stalls" on YouTube....trust me.
The neutral: He's fine cashing chances on the PP (PP2 for you guys)......but do not let him be the one to enter the zone. Also, expect some "WTF was that, Skinner" passes/decisions on the PP.
The negatives: The under-the-radar (kinda) negative with him is there's a real question on if his straight-line speed is gone. At some point last year, he just stopped being fast. All of us on the Sabres board speculated that he had some sort of LBI that he was nursing....but he, Granato and Adams all absolutely swore he was healthy. As I said above, he's still super quick and shifty in short areas......but there's a real worry that his long speed is gone. Which then kind of leads to his major, major issue: he is one of the worst forwards in the defensive end in the NHL. And I'm trying really hard to be objective. He's a master puck-watcher. He LOVES to blow the zone early (which combined with his lack of footspeed....ugh). He seems like he legitimately has no idea where to be in the defensive zone (though to be fair, that may be on our coaching....who didn't have a clue that defense needed to be taught). He will occasionally over-handle the puck instead of playing simply.
In summary: Offensively and in the offensive zone, Skinner still has a ton to give. The reason why we cut bait with him is that it certainly seems like Ruff and company are bringing a fresh "Hey morons, you need to actually play defense" sensibility to our forwards....and there's no chance Skinner would have succeeded in that. But....if you keep the puck in the offensive zone, that's no concern.
Good luck and take care of him. We're all expecting him to be the next Sabres castoff to win the Cup. Either that or you don't make the playoffs. I see no in-between.