Lasers are not useless, you can hit multiple targets from the same enemy, shoot the dragon in the head and the laser will damage all its hit points to the tail, I prefer to use a laser with my HUcast instead of a support handgun or rifle.

Slicers can be equipped by most classes, but their damage depends on MST, not ATP, so a Force will outdamage a hunter with a slicer, but the low ATA can be a nuisance with slicers... also they are very different from pso and psu slicers, not to mention they are powerful in psu thanks to their photon arts, you can hit multiple targets with the slicer, but the moment it hits a target it will come back (they are, in fact, boomerangs this time) so you have to send it again during the combo, and the photon arts are all close range.