So as we all know, the random builder getting 20% of tangos as gold is way too OP to stay in the game. However, getting 20% of tangos as bonus tangos is also OP as it allows random builders to spam the best units in the game sooner than the enemy can handle them.

Because of this my suggestion for a new passive for random builder is this: at the end of a wave, gain 20% of your current held gold as bonus gold. I think this would lead to a more interesting decision making process when playing random builder, as there is a legitimate risk to deciding whether it's safe to hold your gold for a round for a bigger bonus or spend it on towers to be sure you can beat the round. Additionally, I don't forsee this leading to ridiculous gold advantages like the current passive leads to or ridiculous tango advantages like the old passive did.