Having read through the posts, there are too many different posts to quote, so I will try to get them all in this post.
Weight of person: Just because someone is 200 pounds does NOT mean they can hit harder, do more more damage, etc. I've seen 200, 300, 400 pound people who can't move let alone swing a sword, yet Bruce Lee weighed far LESS then 200 pounds and had amazing feats of strength. (Joe Weider, body builder, had to custom design equipment for Bruce Lee because he destroyed it too frequently)
Size: I have seen Aikido masters, Judo Masters who weigh less than I do throw people all over the mats. I have seen 90+ year old Karate masters toss people across the room using only their fingers. (I have been thrown by them too)
Training overcomes, or compensates for, the muscular strength, mass of person, height of person.
We have had this discussion of a weak person being able to "lift the 2-handed sword" in our sessions. When it comes down to the final number, the low Strength bonus gets calculated into the stats. It will take more ranks of training to compensate for the low strength bonus. Some people just have to train harder to be as good as someone else.
It does sound like a good idea to have a strength minimum in order to be able to wield a weapon, but preventing a person from ever being able to use a weapon because they are "too weak" doesn't sound very fair. It took my sister a long time to be able to use a 6' bo staff effectively, but she did it. She's shorter, weighs less, and is "weaker" than I am, but I don't want to be on the business end of her bo staff and now she is far better with one than I am. Why? She trained with it more, overcame and compensated for the "weaknesses" and is now far better than I am. In fact, she has been working with a halberd now which has an 8 pound blade on the end and to me, feels absolutely impossible to wield, but she does it.
The best answer to your question that I can think of thus far is to set a chart that will compare weight of weapon vs. Strength stat or vs. Strength bonus.
10-15 pound weapon : +25 Str Bonus or STR = 90 - 100
7-9 pound weapon : +20 Str Bonus or STR = 80 - 89
so on...
I weigh 145, 6'2". I can break 5 boards with a punch, hammer strike, or ridge hand. I can list every person in my station who weighs over 200 pounds who can't break one single board with a punch. However, those same people can bench press twice what I can...... but, I can do more pull ups and push ups than they can. Weight doesn't mean stronger. I am not what anyone would consider to be a "strong" person.