I am really happy to see this article. I only have one bit of feedback...
"GNUstep has been around since the 1990s, and has re-implemented a substantial amount of NeXTstep, completely from scratch. "
Could we please stop saying NEXTSTEP? This only furthers the misunderstanding that GNUstep is limited to an OS that stopped being produced long ago. Also, we have far exceeded NeXTSTEP and OPENSTEP. It is much better to say that we have re-implemented a substantial amount of Cocoa. Otherwise the article is wonderful. Thank you for getting the word out. :)
GC