Holy mother of... I never saw that line, but it beats Knight's Kingdom II, something I deemed impossible... It doesn't even have any useful parts (not even the mini's!), and the designs look like something my 13-year-old me would put together.
I agree the designs with Fright Knights weren't the best, I very much liked the figs (those torsos and faces, yay!) though, yes even the witch, because Lego hasn't really given us many witches up to this point and thus she's kinda unique. It was also an interesting line for me because of the whole 'Fright' theme; putting scary bad guys in the role of the protagonist was kinda unique for them as well. Practically every time someone creates bad / dark / evil doods, you see at least some parts of the Fright knights appearing.
Of course I may be biased because 2 of my first 3 sets were Fright Knights, but then I agreed the designs weren't all that
I believe Lego wanted to give their territory a bit of a 'ruinous' feel, which is interesting, but didn't work out so well...