Although I appreciate the damage buff to throw barbs and the ability to pierce they are still not viable due to SEVERE ISSUES with weapon quantity. Pre-PTR I build a highly optimized throwing barb and would run out of weapons before finishing a single-chaos santuary run - then I had to wait for 10 minutes to replenish my eth weapons. This is a total non-starter for D2 style gaming.
In order to make this build viable, you MUST incorporate some sort of “replenish quantity” mechanic into the barbarian skill tree. If I were a game developer I would simply add a “+x% to replenish quantity on hit” or “+x% replenish quantity on kill” on thrown weapon mastery, double swing, or double throw (scaling with level). If you want to diversify the Barbarian skill tree, you could add “replenishes quantity/+% to replenish quantity” to the find potion or find item skills (thematic with picking up your weapons from a corpse). Ultimately, as a developer, I’d also introduce this mechanic early (level 12 or below) to help with the early/mid game.
I don’t need the throwing barb to be S-tier, but I REALLY enjoy his rapidly chucking weapons at a distance and being a great single-target killer. Furthermore, the lack of runewords means that most throw barbs in the early/mid game will have to use rare weapons to get by - (I had to use charsi to imbue them) - which cost a lot to repair and have to be repaired constantly.