You don't need to invest wpp in a weapon profiency to be effective as an archer. Power strike alone is good enough.
But if you still want wpf, you can get 50 wpf in 1H or 2H by sacrificing only a few points in archery.
Rememer that as an archer, you will mostly fight in melee 1 on 1 and speed won't be as important as when you get surrounded, which is more common as a pure melee player.
WPF in melee weapons is not that important. It's a totally different story with archery and throwing.