I think TL is going to have a _huge_ impact on that.
And I think there's going to be a big difference between military and civvie.

I can see a TL10-12, maybe 13 ship looking very "20th century
submarine-ish" inside... pipes color coded for maintenance, conduits
easy to get to, etc.

TL13,14,15, you've got room temp superconductors. No longer need 3
gauge wire to carry the power load, you can use 22 gauge. No longer
need big conduit to run it in, either - you form the conduit into the
hull matrix to begin with, since it's only going to be about 12mm
around.
Plasma conduit from the fusion reactor(s) to the M-Drive is going to
be formed in as well.
For additional safety, you put a 2mm crystaliron wall panel over the
whole thing, with disconnects at the corners. That way you can still
get to things if you need to, but if battle occurs, you've got a nice
spall sheet to prevent debris from breaking things.  On lower TLs you
can't afford the weight/volume for adding that layer of armor, and the
maintenance hassle for finding the pipe/conduit/etc is a pain. At
TL13+, you put one of the little heads-up displays on, link it to your
hand-comp, and it'll do an Augmented Reality schematic of the stuff
behind the wall, including highlights of pipe temps, power feed
status, etc.