>>718893117
Add the Gloves of Uninhibited Kushigo (+1d4 with Throw Attacks) and Caustic Band (+2 Acid Damage) to the list. Both can be gotten from Derryth in the Underdark - the former is a reward for saving Baelen, the latter is up for sale.
I've been using this build with Karlach and it's very fun! Turning on Frenzy for Enraged Throw is not even required in 90% of the battles. Multi-classing is a bit anti-climatic but it can improve the build even further in various ways.