Distance = throwing speed of the weapon
You get more distance with heirloomed throwing weapon since they get like 19 speed instead of 17.
This post is about how throwing accuracy (the size of the reticle) is calculated now. 6 or more months ago, throwing axe with 4 PT and like 60-80 wpf was a nightmare. The axe would go 2 meter on the left, and the next axe 3 meters on the right.
Now they always seems to go straight where you aim, no matter how much PT or WPF you have, but i may have noticed that the hitbox of the character seems smaller.
Would be great if, on patch, we would get a message like "Throwing accurary is now calculated by your weiner size" in order to plan our build right.