Pippen did play great the first year Jordan sat out, and they were still a threat to make the Finals, as Charlie Saab pointed out. But then Pippen damaged his reputation by refusing to play the end of game 6 against the Knicks, because Phil Jackson picked Kucoc to shoot the final shot instead of Pippen.
I think Pippen would not have been as good a player, probably not a top 50 selection, if he hadn't played with Jordan and the Bulls. He came out of a small college, unheralded, and took a few years to develop into a super player. Playing with Jordan had a lot to do with that development.
On the other hand, at his peak Pippen was probably the best non-center in the NBA after Jordan. I always thought he would have done the best defensive job on Jordan if he'd been on another team. And I don't think the Bulls would have won their titles without Pippen. Jordan never won one without him, and the Bulls didn't become great until Pippen (along with Horace Grant) matured into a great player.