As we all know, PvP is extremely flawed because of the turn system we currently have. Sure there are some people who win from second, but its very difficult specially fighting a duelist in your experience range.
I took the time to think up a solution for this problem a while back. I think the problem would be solved if KI added a "Quickness" % to cards. Its simple, higher % gets casted first, works much like accuracy. Lower pip spells would have higher Quickness % then Higher ones. Shields, blades, ect.. would be at 100% so they are always casted first. Also gear and pets could boost the Quickness % of the wizard. This way we always have a to shield or heal before the hit comes, and vise versa.
This would mean that the rotation of spell casting would be going back and forth between each team and you really wouldn't know what order it would be going in. In my opinion this is about as ridiculous as taking turns going first (which never made sense to me in the first place). How exactly would you plan anything with a system like this? PvP (especially 4v4) is contingent on "team" play and when the entire battle set up is random, there is no planning involved. Good try though.
Ok, so its a good shot, but that wouldn't (in my opinion) work very well. as 'asutton75' said, the battles would be going back and forth, it would be too confusing for people to keep track of who was going next, the system would also take longer to load as it would have to quickly and efficiently calculate who was going to go first. being second in a battle may be a bit annoying, but in all honesty, the system we have going now is working very well.
But I do like how you put a lot of thought into this, I know all of us at one point or another have gotten frustrated by being second, and you took a very good shot at trying to come up with a solution.