Knuckles is my favorite character in Sonic, by far. I loved how he handled in Sonic 3 and Knuckles (probably one of the best games ever made, imo). His gliding ability, mixed in with his low jumping capability, made him a very fun character to play and very unique to the series. In Sonic Advance 1, they gave him a higher jump which I think hurt the character's uniqueness (plus removing his special paths, and stuff), but he was still my favorite to play.
Actually, I really loved the alternate paths in S3&K. Playing Knuckles was like playing an entirely new game from Sonic's. However, I think some of the paths wasted his talents (see: CNZ1/2, etc.). Some of his sections were focused on speed, which I don't think fit Knuckles' role well at all. However, even with that, Knuckles' routes were harder and less rewarding, but the challenge was very entertaining to play and I loved every minute of it.
I'm going to be redesigning his sections in S3&K. What do you think the best playstyle for Knuckles is? I personally think Knuckles should focus on climbing, avoiding spikes, and platforming, with very few speed sections mixed in. Also, I think he should be given access to shortcuts/alternate routes that take advantage of his climbing ability, and entering Sonic's paths occasionally.
What's your opinion on the matter? How should Knuckles play?