Fair play to them. They are in a bit of a bubble here in Prague as noone from my Czech/EU network has worked for them, but still the product is great, their treatment of community - excellent and I wish them best of luck in the future as well.
P.S. I am currently shilling for Jetbrains Spaces to the leadership :D
to be honest most of those neat things exist in many other languages - for example all the slavic languages + the more conservative germanic ones have a way root+prefixes/suffixes that plays a similar role. also most of the slavic languages have separate endings for feminine/neuter plural and slovene even has the dual.
Apparently, to a person who only knows english, which is a very inconsistent and mixed language, these features could look extremely neat, but the reality is that they are quite common.