Xenk was great - that walking off bit was apparently because they hadn’t called “cut” yet and he just kept walking. So they let him, then turned it into a gag.
I think he was supposedly crafted as a replacement for a planned inclusion of Drizzt as a character, but I like my headcanon that he’s basically the DMPC sent to deus ex machina them out of their worst fuckups.
I don’t know enough to say whether that’s what did it in or not, but it was still a phenomenal movie that was liked by critics and audiences. It’s definitely a marketing problem.