In most cases you can go with just one point in all the passives. I sometimes sink extra into a couple of them until I hit the really steep deminishing returns.
You do want full pierce, but with razortail belt, and +plus skills depending on your gear, you should get pretty close to 100% with only a couple of points at most.
I have also dropped the valkyrie in favour of decoy and haven't looked back. That was on a strafeazon, though I plan on making a javazon soon and don't intend on using valkyrie.