I own a pair of LT4s. I've put thousands of miles on them. I really like them and think the twist locks are great.
However, if they were offered in a flick lock, I would buy a new pair in a minute. I have a pair at home that is stuck. OK, I can make it work by squirting lubricant in there, but then it slips. Once the lube is all used up, it gets stuck again. I believe the problem is due to the little rubber things wearing down. I've been told where to get new rubber things, but haven't gotten around to getting them. Plus, I have to figure out the exact size of the rubber things. I use heavier (metal) poles this time of year anyway (on snow) but I need to get it fixed by July or August (when the snow melts).
I don't think it would be easy to add flick locks to an all carbon fiber pole. Flick locks work by compressing the metal. I don't think it is a good idea to compress carbon fiber (if it is even possible). I can imagine an external locking mechanism working, though. This work similar to flick locks, but not quite. It would use rubber and not be as streamlined as either a flick lock or a twist lock, but would be more reliable and long lasting than a twist lock. It would take some research and design work, but in my opinion, it would be worth it. There are plenty of people, like the author of this post, who simply don't trust twist poles. Some of them by other brands, while some of them buy LT3s.
Oh, and I think * * is a dog: http://en.wikipedia.org/wiki/File:Internet_dog.jpg :)