Modern Clojure includes that - it's deps.edn (though I'm good with Leiningen).
And ditch Emacs (unless you are already using it/used to it) and try VSCode + Calva that runs basically out of the box.
Exceptions... yes.... they are clear when you know what they mean, but it takes time, because they are so long.
Startup... you only start a REPL once, so does not really matter (to me at least). For compiled code, you can try GraalVM, that has zero-ish startup time - because all static initialization is resolved at compile-time.
And ditch Emacs (unless you are already using it/used to it) and try VSCode + Calva that runs basically out of the box.
Exceptions... yes.... they are clear when you know what they mean, but it takes time, because they are so long.
Startup... you only start a REPL once, so does not really matter (to me at least). For compiled code, you can try GraalVM, that has zero-ish startup time - because all static initialization is resolved at compile-time.
Just my $.02
Edit: Calva also includes a debugger - never used it, but here it is https://calva.io/debugger/