Not sure what you mean by sluggish but I'll bet thats a by product of a boat that tracks better. I may be wrong but I'll bet the new BIGGER boats are also the best tracking boats ever built. Like 6balls said above, all it has to do is make it around the islands with ease and then be able to pull a skier through the course on a straight boat path. The bigger the boat the stronger the pull too, not so easy to pull the boat down.
I'm kind of playing devils advocate above, I too think I would like to see a smaller slalom boat. However, I'm starting to talk myself out of it.