When I make levels for Lix, then to me, all skills are equally part of the game, so they are all available to choose from when I need a particular tool for a specific-solution level. I certainly don't
use them all equally; runners and fling-bombers are my least used skills, but I have used both on occasion. I really like the uniqueness of the batter; the possibilities opened up by the jumper-climber; and the way the walker has many possible uses and the player never knows how it will be used on a particular level.
For the type of level I'm best known for -- "resource management levels" with many skill types, only a few of each, and no single intended solution but finding any solution is hard -- again I usually include all the skills and try to find a solution while keeping my skill usage nice and balanced. The new skills really help with this, because builders are no longer the only constructive skill; and the walker and jumper can isolate a worker without draining the constructive and destructive skills.
By contrast, I'm not a big fan of the new NeoLemmix skills, and in the pack I'm working on, I don't use them at all. They just don't seem to me to have the same cohesion as a set that either the original skills or the Lix skills have. The disarmer and swimmer are too simple, being just what Simon has termed "key skills" -- each gets past a particular type of lock and that's all it does. Gliders have the potential to be really fiddly and annoying, especially combined with updrafts. Stoners are overpowered because they can be assigned in mid-air; and the irregular terrain created can also lead to really fiddly and precise solutions. Platformers are a good skill, of course, but as I'm used to the Lix platformer, I find the NL one really awkward to work with. Walkers are the same as in Lix, but... when there's only one or two new skills I might consider using, I prefer the purity of sticking with the original eight