> - Fixing the order of hook invocation in a real world scenario where
> hooks are used to implement plugins using only (add-hook! hook proc
> [append_p]) is not possible in all cases. The append_p which put the
> procedure at the end of the hook is a weak and partial solution to
> some coupling between the hook's procedures that should not happen in
> the first place.

> As such, hook's procedures should not introduce coupling with the
> hosting application or between the procedures.

> In the case of multithread environment the ordering would not be
> deterministic, so there is no point in prescribing order.

I'm convinced by this reasoning.