One thing I've thought about on and off for Gideros is having the ability to switch Lua versions. Luau performs better than Lua, which is great, and then LuaJIT with code written in a JITty style, making use of FFI, is in another league. On platforms that support it, so fallback to no-JIT LuaJIT, Lua or Luau for HTML/iOS would be necessary.
But whatever the pluses and minuses of any particular implementation, the concept of choosing a Lua version to use seems like a solid, future-proofing idea. Even if not for current implementation, developing Gideros in a style that doesn't more tightly couple to a specific version should be something to think about imo.