Trust me it is, even down to the token female sidekick.
Blade Trinity isn't completely awful, if only for the fact that Ryan Reynolds is awesome in it. The original Blade arguably kickstarted gritty comic book movies, and is really quite special. It didn't completely destroy the series, but it was certainly a step down, similar to how the original Resident Evil and original Underworld are grittier and superior to their followups.
I know what you mean, most are guilty pleasures, if not exactly masterpieces. Maybe Hellboy? I also think Supernatural (TV Show) is incredible for what it's worth, especially in the first few seasons where they focused more on monster hunter, and less than an underlying story arc.