Assuming 1.6 ships soon with all the nice improvements (which I won't mention here in order not to spoil the surprise) my personal list shortened to:
* Cyclic imports. There is significant progress here <https://github.com/timotheecour/Nim/pull/809> thanks to Timothee. * Attach more operations to types or some other scope extension mechanism (see <https://github.com/nim-lang/RFCs/issues/380> ) * Incremental compilation. Of course, others think it should be: * Not nil. * Better sum types. * Working concepts. * Faster "method" implementation. But these don't change how bigger programs can be structured and so are considered less important by me.