I have doubts that a kitten or goblin waterfall actually works. This is because my marksdwarf squads almost never become desensitized, despite overseeing the slaughter of goblins (that's mostly completed by axedwarf squads, who do become desensitized rather frequently). I suspect that the only way dwarves actually become desensitized is by direct, hand-to-hand slaughter.
This would be really easy for anyone to disprove-- just show me a screenshot of a dwarf that doesn't really care about anything anymore, that doesn't have any kills.
Glass windows don't have a lot of uses. You'd use them when you somehow want dwarfs to become interrupted by an enemy, but not be vulnerable to arrow fire. So they should be useful in sentry positions (vampire closets, etc). For most purposes, you can use floor grates or bars instead (which actually do block arrow fire as well, don't ask me why). (I was considering a design for automatic lock-down and/or differentiation between trap-avoids and diplomats/merchants using a vampire at a window, but if the vamps think they have a path to your fortress, they'll abandon post every once in a while, and you have a false alarm, and if they don't have path, then either they won't abandon post to try to engage an enemy, or else your diplomats don't have path either.)
Glass windows can be used to fight cave adaptation-- but so can any other material. Once a tile is exposed to the sun, you can roof it with anything at all, and the area will still nauseate dwarves/increase sun tolerance.