I think I remember reading at one point that Perfidus is intended for a group of lvl 14+, am I wrong about that? If not I'd wonder why then it's a problem that a lvl 10 character can fight a few werewolves, or rather, what lvl you think would be more appropriate to manage that at? If not ten, then what; 13, 15? If a group of lvl 14's can kill pit fiends then I have a hard time swallowing that one couldn't take on some werewolves. Maybe the problem isn't so much the strength of the monster but peoples perception of what a characters lvl indicates about their strength/ability. You may only have half the possible lvls at 10, but consider that a lvl 10 wizard has access to over half the spell circles which include some pretty powerful spells. By lvl 10 you're a seasoned adventurer, so if you're the fighter type, why shouldn't you be able to handle werewolves? Do we really want werewolves on par with creatures that should obviously be able to snap a neuri in two just because we don't comprehend the power our characters represent?
Additionally, replacing packs of werewolves with random werebats and low level vampires is by no means an even trade. Werebats are a joke, and single low lvl vampires aren't much of a challenge either-not compared to packs of werewolves-especially the stronger spawns like abberants and mountain loup-garous. Neither are ghost creatures. Getting rid of werewolves and trying to replace them with these things would make night time a joke, and we'd be seeing another thread pop up shortly after about how no one fears the night anymore (again), but it would be entirely valid because no one would have a reason to. Werewolves might be too easy in peoples minds, but they're the only thing keeping people from treating the night like the day.
In summation, get some perspective on how powerful your character is. You might not be max lvl or even what you'd consider "high" level, but you're no chump if you're able to solo them. Personally I think they represent a challenge fitting of them. Move on to more "epic" fights or sit back and play the seasoned veteran for the noobs-warning them about neuri and giving them tips on surviving out there if they insist on going.