They DO use nades more liberally but the ones that know what they're doing can really mop up on the later Abyss stages. I mean, why not use 'nades when that's the intended niche of your character? It'd be like picking Raymond or Morgan but never using Magnums.
JPC players are actually the biggest wild cards simply because they are so commonly used, you have no idea what kind of player you're getting with them.
Keith players are probably the most annoying. Everyone like to spam his knives but most people wind up taking a pounding to do so and usually they bite off more than they can chew. In the HD version, however, Keith is a good ally to have as knifing is easier.
Well, I suppose it's time to get kidnapped again...