1v1, against equally geared casters you are pretty much as good as dead. Even if you get the drop on them (unless they are fighting mobs or at low HP).

My main is a 60 warrior, and this is why I'm leveling a hunter now. I like being able to do something in world pvp and not rely solely on others. If I had a buddy to duo I would for sure go warrior+priest, but that's just a pipe dream right now.

So here's the thing, WPvP is unbelievably chaotic with tons of incalculable factors. The smallest of things can give you an edge over your opponent, ex: grenade landing, resists, misses, etc... You could even be by chance talented a certain way to deal versus a certain class.