I am catching a whiff of judgement in your reply. You are the person on the team who knows the ins and outs of the language and is proud of it. You are a valuable member of the team, but I don’t want a whole team of you. There are other skills that are just as important in getting something “delivered” as knowing all the syntax.
I said there are other skills that are just as valuable that I look for when building a team. Exhaustive knowledge of a language is a perfect skill for writing docs, training, performing interviews & doing code reviews. My main point was, it is not a required skill to be a “good” developer, like you seemed to imply.
I said it's possible to keep a full model of how some languages work in my head and I find it helpful to, not that it's mandatory. I even said that I can't do it in C++ and that I've delivered C++ projects, so I don't think my phrasing implied that it's required :-)
A good developer ships high quality software. If the situation calls for it, she ships it in C++ or ECMAScript 3 or Microsoft InfoPath. Nothing else is required. Many other skills are very useful, like good communication skills or some understanding of business or math or how computer infrastructure works.
These days I seldom write code - maybe one out of 4 or 5 work days I'll spend more than half an hour typing code in a text editor - and yet having a good model in my head of how my language works, how my database works, how my caches work, how my network works, is something that's very useful to me everyday. Other talented developers I know don't have that, and I recommend most of them to spend a bit of time acquiring it because it's worth it. More talented developers than me that I know and work full time in C++ don't have it, and sadly I don't recommend they get it because I think it's beyond their abilities. I think that's a negative attribute of a language that has some other very positive attributes (like its culture of just writing code that solves problems instead of obsessing about tools and DX all day).
