zlua is a maintenance problem with low bang/buck as implemented...?

I admire and enjoy Lua. I don't know what it's really doing in ZFS though (channel programs? wha?), and least of all why we need to put it in the darn kernel if it's not twiddling hardware bits or deeply coupled to kernel structures. It's a frickin' interpreter for a scripting language to support one feature, and as small and elegant as Lua is it hurts my head to think of it in ring-zero. So while I admit my caveman brain is having a knee-jerk reaction to something I don't fully understand, nonetheless zlua is 15KLloc of code which:

• is heavily modified from upstream in ways that create unique issues and make it harder to accept upstream fixes
• is a constant source of bugs and holes (see: git log)
• does not appear owned or maintained short of when users or code analyzers tell us it's full of bugs and holes
• surely should live in userspace if it should live at all