Naming of staff-staff-spacing

[Noeck]

Hi LilyPond developers,

the conversation in the thread »How to increase the distance between systems?
(new try)« has drawn my attention to vertical spacing settings and I have one
question concerning:
http://www.lilypond.org/doc/v2.18/Documentation/notation/flexible-vertical-spacing-within-systems#spacing-of-ungrouped-staves

Why is »staff-staff-spacing« a function in contrast to all other A-B-spacings
which are alists? I mean, I understand the extra layer because of grouped and
ungrouped staves. But from a user’s perspective this is confusing. Wouldn’t it
be more straight-forward to have identical objects (alists) behind these
consistently named properties? I.e. a different name for this function and
reserve the consistent name for what is currently the 
default-staff-staff-spacing?

This was not such an issue in older versions because only experts knew how to
change components of this alist using #' etc. And if the function is replaced by
a complete alist this is also no problem. But in recent versions one can do:
\override VerticalAxisGroup.staff-staff-spacing.basic-distance = #15
and for all other spacings except staff-staff this works.

I mean, I know why the design is like this, but wouln’t a different naming help
to make it understandable for users?

Cheers,
Joram


PS: In case you ask for suggestions: Experts on this will find better names, but
how about:
staff-staff-spacing         -> general-staff-staff-spacing
default-staff-staff-spacing -> staff-staff-spacing