I don't think TNG neutered them. The Borg still sent chills up my spine in "I, Borg". The "Descent" Borg weren't part of the Collective and I thought the idea of rogue vicious Borg unleashed on the galaxy was particularly scary.Anwar said:
B&B didn't "neuter" them, it started in TNG itself and UPN's insistence on Borg stuff to get the ratings up didn't help matters.
FC had the Queen. An idea I didn't object to in idea but in execution found disappointing. Instead of a Locutus type figure she was this emotional femme fatale proned to the same sort of fits of anger and scorn fo being rebuked by Locutus.
I thought they were scary in Unity, Scorpion, Raven, Hope and Fear, Drone and up until the last ten or so minutes of Dark Frontier.
After that they weren't scary but were used in some entertaining stories like Unimatrix Zero or at least Part I.