My complaint is that the entire concept on which LSPs are based today — each LSP reimplements all functionality itself, the editor is only a dumb textview — is wrong.

Language servers should expose an AST, not some actions. Language Servers shouldn't even know where the cursor is — or how many there are.

With a proper LSP, you can also write a linter just by using the protocol, you can call the same action on a thousand places at the same time, and the refactoring functionality is implemented only once, and reused everywhere.

The entire design of LSP is flawed.