yes they have insane 1v1 damage potential but in a game defined by stuns it doesnt really feel like it helps them, the nightmare meta has essentially been solved for months because their ability to create and abuse dark areas is so hampered by the facts that
a) they cant do much to people dragging lights behind them
b) they cant wear most clothing items for protection
c) they're reliant on trying to get normal gamer loot (radios, sunglasses, sec gear) for survival, to the point where i would argue nightmares are weaker than normal seccies/greytiders who know what they're doing
most importantly they're one of the few antags that drops gamer gear (organs) on death. im not saying friendly antags should be encouraged but the moment you are confirmed to exist as a nightmare every single seccie/borg/tider/powergamer on the server is gunning for you, and as mentioned having a bigass knife arm and spooky dark powers isnt really that strong when all of those gamers know how to easily counter you and have such a clear incentive to do it, perhaps moreso than other side antags
i dont really know what nightmares should get and idk if id say they should even get straight buffs (trade damage for survival tools??) but they just feel woefully underprepared for the current meta