Anarax
Master Black Belt
I think there is a difference between training and then coming up with a ruleset that allows you to do it in competition. In training it is relatively easy to acknowledge when you got hit on an afterblow or recognize that even if you were fractionally faster the other guys shot would have landed as well. Our general policy is that any trade is a bad trade, we tend to emphasize "blade based" sparring because it tends to be more technical than stick based, I find that is easier to go from bladed to stick assumptions rather than the other way around. My own group uses padded sticks for beginners and light rattan for my more advanced guys.
I really hate the WEKAF approach, great for cardio and hitting hard and not much else.
Obviously I am a fan of the DB approach, though the Gatherings are usually "this is a stick" and we use bigger sticks than your average FMA school to make rattan actually useful as an impact weapon. When other weapons are used more care is taken. See this highlight reel as an example, it has a lot more sword in it than other reels:This isn't a ruleset, it is an acknowledgement that we aren't actually trying to kill each other, literally the main rule is: "be friends at the end of the day." The caveat is that we can still be friends if I break something of you as long as it wasn't malicious, and hopefully it was something unimportant like a finger, becasue that is just the cost of playing hard.
For a competition format I really like what some of our area HEMA groups are using, which is a stop action tournament but has provisions for afterblows and double hits. Double hits are really frowned upon and has a highly negative influence on the scoring. The ruleset that these groups use are from CombatCon. 2016 Tournament Rules - CombatCon
WOW, this is the first time I watched their 2017 video and I really liked what I saw. They have really cleaned a lot of it up and a lot the participants look like they actually train in weaponry. The only thing I thought was excessive were the repeated blows to the back of the head and neck with the weapons and the 3 sections staff was a little hard to watch. Other than that they've really improved on just about everything