It's cool to read that treeform is using Nim at reddit (and helps explain why he's so prolific!). I see the same question sometimes asked "what is Nim's killer feature", "what is Nim better at than other languages" and the answer given is usually "there is no killer feature, Nim is great at lots of stuff!". But I would argue Nim's killer feature is pragmatism. I think it's the most pragmatic language I've come across…
I hope I won't start yet another flamewar.. Have you tried D? It's also a language I'd call pragmatic.
Haven't tried it really only due to a lack of time (and I've played with too many languages in the past 12 months)