1) Bashers can "widen" Laserer tunnels just like they can widen Fencer tunnels. However, in case of a Fencer tunnel, this makes it Shimmier-friendly (which the default Fencer tunnel isn't). In contrast, a Laserer tunnel is Shimmier-friendly by default, yet sending a Basher down the slope will make it Shimier-unfriendly, because the Basher will give the ceiling dents of 2 pixels in height.
This is a nice contrast, I think. While the Laserer and Fencer are similar, with these important differences in the detail, they're indeed shaping up more and more to become the Stoner/Stacker couple of destructive skills.
2) Water can EDIT: NOT stop Laserers.3) The Spearer has a great unique application in which, because the spear is longer than its competitor that is the Stoner, it can oftentimes
create the right spot from which other things need to be done - meaning without the correct Spearer placement first, the correct position to assign a given other skill does not exist yet.
This is indeed huge puzzle potential that's unique to the Spearer. Because where in levels so far, if the solution is cleverly hidden in plain sight, the correct spots to assign all the skills are there - you just need to identify them.
With the Spearer however, it might indeed be that there is no correct spot to assign a certain skill. So you look at the landscape and find nothing. Now you need to factor in where you might be able to create the correct spot by throwing a piece of terrain there.
In the older of the two newest example levels, this "skill for which you need to find the right spot" is the Jumper: The Climber wouldn't have anything to land on (and to jump off off) if he hadn't thrown the spear there first.