In terms of features, it's not so much that Nim is missing features I need/want, rather that the ones that it has are in varying states of usability, and may change quite a bit.
As has been mentioned in another thread, the deprecation of generic methods in 0.20 is of concern. IMO if method is going to stay, it should work with generics, otherwise a different way of introducing dynamic dispatch which does work with generics should be introduced. Concepts and static[T] were very buggy when I tried them, I don't know what their current state is. I see that concepts are no longer in the manual proper, but moved to some experimental annex. That's better than when unimplemented features were in the manual, but I'd like most of what's in that annex, especially concepts, to be fixed and part of Nim 1.0. I'm far less concerned about newruntime working out (after all, modern C++ works in spite of the tons of historical baggage C++ has) than I am about these existing type system issues.
