It would be really nice if we could have some sort of real PVP system where we could 1v1 our friends and guild mates at least in a live battle. The battle AI system is really crappy and never plays out the team like it should be played.
This will never happen in GoW. Has been stated by the devs many times over the years now.
It might work between friends and guild-mates, but I feel other modes would see people rage quit as soon as they started to lose.