I don't participate much in these combat threads due to a lot of the aforementioned reasons. However there is a way in which you could play and simply write that should be acceptable to both parties. If you have people examine both characters beforehand and judge them according to their weaknesses, strengths, intelligence, experience as well as combat behavior it shouldn't be too hard to reach a consensus on who should win the fight, how they win it and even how they react to each others. Sure some may argue that it limits 'freedom' but just as we limit character traits for the sake of balance and fairness it shouldn't be too hard to predetermine the outcome of a fight and write accordingly to reach that conclusion.
If two characters have roughly the same 'stats' it should be up to combat behavior. If not, Personality, or in other cases experience and maybe even luck(lucky slip on the floor?). Hence why I often stress the importance of detailed profiles but not to the extent where it seems like you're reading a novel. Short but sweet but has enough detail to get a good overview.
Another issue with fights is overdodging, blocking, and the like. In the show itself we see that the characters often DO get hit by attacks with few exceptions(Pyrrah) especially if they're on roughly the same level. Overthinking and lightning fast reaction times don't happen every attack especially when faced with an opponent they've never met before. So the end result? Get hit. take the damage. Have the character react accordingly. Combos are hard to pull off due to the somewhat turn based system we often employ but perhaps a little pre-planning such as an acceptable feint then a three hit combo that caught the opponent off guard can be agreed to. Only problem with this is response time due to varying timezones or schedules. Opening a discussion thread for you fight is also an acceptable way to discuss things while having a referee so to speak or while taking the opinions of others as well.
From what I see the most common problem with my suggestion is that some people tend to be too hard-headed and forgo advice or even suggestions due to pride, confidence, or even spite. Pick your opponent's wisely not just for the sake of a good fight but for the sake of good writing. If someone's too stubborn what usually happens is people getting mad and dropping the thread or having them walk-out the fight. And believe me nobody enjoys that.
This may be an RPG but don't forget the essence of what we do is writing. It is somewhat a game but it takes effort to plan something that's pleasant to read or enjoyable to write and since we rely on interactions with one or more person in a thread that makes it increasingly difficult but not impossible. A little patience can go a long way. Also not being a selfish dick. People never enjoy those.