I think 4 point makes perfect sense. Pardon my possible ignorance to previous posts as I've not yet read (and will likely never read) the previous posts, but here are my two cents.
When my friends asked me why 4 point made sense, I told them all to look at their DOA
fighting statistics. All of them had around the same statistics for attacks. While Highs made up about 20-30% of their attacks, lows constituted for about 15-25%, normally close to a 30/20 split for highs and lows respectively. Then, viewing their mid strikes, they had, around average, 50% of their lifetime attacks as mids. I'm not saying this is true for everyone, but not only did I expect it at first, but the 6 people who viewed their stats all had similar data to show.
Basically, my point is this: If mids count for around 50% of a players arsenal and highs/lows counting for about 25% each, it makes sense for mid holds to be slightly tricker to get off (aka, cut it in half by giving it both a punch/kick option) or else those would be the only things people would spam (since statistically, it's their best option to stop a combo).
In fact, that's what the randoms on Dimensions normally reverted to - mid counter spam.
Agree or disagree, I don't really mind, but to me, the 4 point counter system makes the most amount of sense. I'm not saying a 6 point wouldn't be good, but I think 4 point makes the most sense.