I dunno, the spiders in the original game were pretty annoying too: in fact much more so in my opinion. Curiously enough, this wasn't a battle that I found excessively onerous other than its duration: "curiously" because I'm usually pretty crap at combat and tactics, so it definitely is possible, if a bit tiring. It's best to keep your party out of their immediate vicinity since they tend to throw up a curse when they snuff it, which is always annoying and occasionally slightly lethal.
The mêlée/ranged thing might be significant since I usually just have one mêlée fighter in my party: the Grand Prawn with a two-hander. The others are always a mix of archers and mages.
