No D tag. :(
Why not use the language server protocol so that people can use it in the editor they prefer? A standalone IDE feels like precisely the wrong idea.
Personally, in my experience, I’ve found language servers to be janky; performance is often slow and indexing behind current state. IMHO, you have to make intelligence native to the editor, otherwise, it’s not worth the hassle. (Hence why I use vim completely vanilla, and Visual Studio for anything that needs the big guns to be effective.)
It’s just that there are so many languages now that having a heavyweight IDE for each of them is impossible. Language servers might be janky, but they do give some IDE features in a familiar environment.