There is a difference between quickness and mobility. Pronger isn't the faster guy, but has the best mobility in the league. I'm sorry you're overrating Karlsson if you think he's going to be the same player as Keith.
Not saying he will be, but your underrating him if you don't think the kid posseses all world skill and elite potential.(he's already a better player then what Keith was at his age).
I really encourage you watch him more closely next year(although I'm sure people will start to hear his name a lot more often once we get some more talent around him), He's one of those kind of guys that's worth the price of admission.