100 wpf makes melee useable, especially if you go for relatively fast weapons. 130 is about as good as you need. Above that, it helps yes, but you'll be kidding yourself if you think it will make a real difference - at that point your own skills will be far more important. For a support role, even less than 100 is still useful if combined with high athletics and light armor. Since you are not fencing, you rely on timing and a quick step-in to deliver a hit, then retreat between your allies.
The only exception is a super spam build in which you go all out agi, 180+ wpf and use a fast weapon. You'll hit like a girl, but you can kill other girls if they wear pajamas to battle. I am not sure how limited it is now when the requirements for weapons have increased.
