Well, it seems to be working very well, but I am still in development mode with one customer and very little scripting going on. I will know more after general public is going to use it and will try to use things I haven't think about.

I am not that concerned of Wren failing as a language, but I looking for a ways to prevent users write code that doesn't work without having to know what is going on, which is something Lua is excellent in (typo in variable name in if statement? Valid code for sure)