Roenick was fast with a good shot, would throw what little weight he had around and played with an edge including some big open ice hits that made him a fan favorite. He wasn't a tremendous passer, but he created a lot of space with his speed and aggressive play to open up opportunities for other guys on his line. He was perfectly adequate defensively, though never a standout. He was absolutely a bonafide #1 C and one of the best players in the league prior to his knee injury. After the injury and with his balls to the walls style beginning to pile other nagging injuries he slowed down both in terms of speed and in terms of aggression. His last year or so with the Hawks (and the rest of his 20s after departing) he was still a skilled 1st line player but not the dynamo he had been previously.
When he first came up I seem to recall him playing with Steve Thomas on his wing most frequently and then a rotating cast on the other side. Once Savard was traded and Goulet was acquired Goulet-Roenick-Larmer was pretty frequent although other guys like Gilbert, Matteau and Noonan would play with him too. Then in 94 they formed the RAM line for a while with Amonte and Murphy. Poulin also got some time with him. After his knee injury and the team acquired Nicholls and brought back Savard they mostly played Roenick at LW when everyone was available (Roenick-Nicholls-Murphy).
Roenick would have been just as dominant in today's era as back then. The only thing he would need to change would be the edge he played with. He went to the penalty box a lot back then, and if current fans thought Andrew Shaw took stupid penalties, Roenick would have driven them insane. He would have had to reel in that aspect of his game.