Stungun was stupid broken, but one tiny change could make it fair.

IDK how much I'm gonna be roasted for this, but you could leave stungun exactly how it is, but make it a specialization. You want your stupid free kill? Fine, no grapple, dashes, or multi-use invisibility for you. Make it a little longer than the normal cooldown, and it becomes way more balanced. Plus if the use the stungun to engage a fight, they really run low on offensive options up close besides the main weapon. Just a stupid little thought I had.