The aforementioned Stacker/Stoner trick can be done without frame stepping - it just requires good timing
Fair enough
And here is yet another one-way step made with two freezers and a fencer...
OK, so you're looking for a way to make a one-way step, I see. Using 2 Freezers instead seems to work nicely, as does using a Jumper>Bomber combo (I tried this in real time and it
can be done, with a bit of practice).
The Laserer is the cleanest way to do it, but I suppose it does mean the level designer may need to place steel in the laser's path if they don't want other parts of the level to be destroyed. Either that or add a cancelling skill, which is also not ideal.
The angle of the Fencer tunnel is meant to be that of a Miner and a Builder bridge, so that these skills are compatible. I wouldn't really wish to change this without good reason. In fact, there has been talk of making the Fencer tunnel wider to allow it to be Shimmyable, and this is more likely to happen than an angle change. This would make the "one-way step" even lower.
So, maybe the most ideal variant of this particular interaction (i.e. Stacker>Stoner) is something we lose by not having the Stoner. This, along with the spooky aesthetic that plays nicely into zombie levels, is a somewhat convincing case for bringing the skill back. The reasons against doing so (it's fiddly, it bloats the skillset to 25, it costs a lem, the Freezer is a more evolved variation of the same idea, etc) still seem to outweigh it, though.
Also, even if the Stoner is brought back at some point in the future, I'd like to see how we manage without it for at least some time. SuperLemmix offers 3 new skills plus a new state (the Dangler), new talismans (Kill All Zombies, Play in Classic Mode, Play Without Pressing Pause) and a number of physics changes (wall-bouncing Jumpers, direct drop, one-way-field sides) that we ought to explore before rushing to bring culled stuff back.