Anyhow, coming from python, I hardly miss a switch/case structure but, an yield would be certainly interesting to gave upon. Also, type annotation would be very nice (helloooo ravi). Large code-bases could benefit tremendously from it.
Regarding OO with Lua, I hardly miss a built-in "class" support, but the lack of a standard interface for OO Lua libraries is a big bummer. Lots of incompatible OO libs. Something like: "if you want to build a lib to do this, try to make it compatible with this interface/behavior".