I'm not so sure this comparison between Shimmier and Platformer holds up:
- The Platformer is not supposed to gain height. However, if it were possible to assign a Platformer while a lemming is walking on completely flat terrain, he would still gain 1 pixel of height. This could potentially be abused.
- The Shimmier, in contrast, is always supposed to gain height. And gaining height has always been used for various purposes, such as getting over an obstacle, breaking a fall etc. The same applies to cancelling skills: Any destructive skill can cancel a creative skill, any creative skill can cancel a destructive skill. In cases such as cancelling Bashers mid-swipe, this can already be done with both Walkers and Builders, so I don't see why the Shimmier would make it more broken. Rather, this is a general feature of NeoLemmix, allowing to time skill assignment in such a precise manner that mid-swipe Basher cancellation can actually become part of the intended solution. In most other Lemmings clones, this would usually be impossible to get right.
The Shimmier lacks two important features in comparison to the Walker that already serve to make it much less broken:
- Shimmiers can't turn lemmings around.
- Shimmiers can't cancel Blockers.
Especially the first of these two restrictions is one I like to build around in my levels: One of the few ways I know to use a Shimmier to turn a lemming around is by making him a Glider as well. Then, you need a wall that does not touch the ground. As a regular Walker, the lemming would continue to walk into the previous direction; however, if you make him a Shimmier, he will fall at the end, bumping against the wall as a Glider, and thus turn around.
As you can see, this requires a comparatively specific terrain shape.