As always,
it totally depends on your playstyle.
For a 2h, you really dont need that much strength.
This 22nd peasant (Phase or something like that), I think he has 15 strength but 10 or more ath. Doesnt have to use right mouse button very often.
Athletics is very important in melee.
Look at all those crossbowmen. They have only 15 strength, not much wpf in 2h, but with their high ath they are often harder to defeat in 1 vs 1 than a strength 2h (that cant parry very well).
Main advantage of ath is that you dont need that much parry-skill. You simply learn to use your high ath to stay out of enemies shorter weapon reach, and stab, backpedal, so on and so on.
You, my friend, are cursed with your high ping, so you cant get too much ath anyway.
Lastly, high ath makes dodging arrows easier.
Me personally I think 6 power strike for a 2h is enough.