Toss this weapon in the trash and redesign it. Who the heck uses a 10lb throwing weapon? Mechanically this weapon doesn't make sense. Why would you both be able to control someone connected to the harpoon with an opposed str check AND be able to rip it out as a full round action. Don't you think that trying to control the harpoon with a strength check would rip it out anyways? I don't really see a difference you are pulling on it as a full round action either way.
Isn't the point of a barbed anything is to have it stick in the opponent without coming unlodged in order to annoy the heck out of something and gimp its ability to move. Barbed spears, which this essentially is, used for hunting are meant to stick in the prey to impede their movement and agility not be ripped out to do extra damage. I would say redesign it to allow for an opposed strength check so someone cannot move out of a certain range depending on rope length and maybe reduce movement/ dex penalty. Somehow I believe that hitting a human with a 10lb barbed spear would really stick very well anyways but this is just speculation.
Isn't the point of a barbed anything is to have it stick in the opponent without coming unlodged in order to annoy the heck out of something and gimp its ability to move. Barbed spears, which this essentially is, used for hunting are meant to stick in the prey to impede their movement and agility not be ripped out to do extra damage. I would say redesign it to allow for an opposed strength check so someone cannot move out of a certain range depending on rope length and maybe reduce movement/ dex penalty. Somehow I believe that hitting a human with a 10lb barbed spear would really stick very well anyways but this is just speculation.