> Isn't indentation is a matter of personal preference? That's why the
> methods for controlling indentation are user-dependent.

Kind of, but on a team of people working on a single project with requirements for all to adhere to the same indentation scheme, this falls down. This scenario is common and desirable.

This information would ideally be encoded in the project's lisp side and communicated to emacs via slime.

I believe the mechanism for swank to communicate indentation already exists as this is how the macros are properly indented and would only need to be broken out if it is not already.