This weapon can surely work for campaign because the +2 to shaman is great for pet builds, I might be interested in trying to make an endgame build out of it, but would have to investigate additional factors. However I think it works better forfeiting the +2 to inq and use a class that has physical resist reduction. Since your main damage skill is in shaman, I don’t think this is a very big sacrifice.
Also I don’t know if you intend to use briarthorn only, I just happen to also have a pierce warder hybrid pet build, but it works better with swarmers: