I still think that the current (5.2) __pairs and __ipairs metamethods are a fairly good compromise. But, there are places where I'd certainly prefer a __next to __pairs. I'll still sometimes get into trouble by writing code designed to work on standard tables, only to hit bugs when lua_next fails on my userdata proxy tables. It's never that hard to fix, of course -- but it does feel a bit inconsistent. API functions like lua_getfield() respect proxies, so why not lua_next() as well?
