[simiones]

I think much more than language syntax and features, it was impressive until ~5-10 years ago just how advanced IDEs for Smalltalk and Lisps were compared to any other language. There has been a massive catch up in recent years, though I think many dynamic languages are still behind on their IDE support compared to these ancient technologies.

[pjmlp]

Edit and continue still aren't as good as those IDEs are capable of.

Then there is the whole stack REPL development experience, which probably Powershell + .NET + COM/UWP on Windows is the closest we get today.