As far as DSLs go, Supercollider uses OSC internally. Csound and Pd both
support it, too. Don't know about Chuck, but I'd imagine it either does
or it's high on the to-do list.
IMNSHO regarding your subject question, I'll would
start with MIDI as
everything else does; e.g., alsa-seq API is a pretty high level
You mean it's historical then? ;)
abstraction and you'll hardly notice that MIDI 80s
byteness ;) Then, some
way down after, whenever you feel MIDI control space is exhausted, you can
add OSC for an extension or even substitution.
IMVHO, I think this is a little bit backwards (no pun intended) - if the
API design is limited to MIDI it won't be easy to open it up further but
built with OSC in mind you can expose a subset of it as MIDI.
The only disadvantage (and it is a real one) OSC has is lack of
adoption. I wouldn't recommend choosing MIDI simply because all the
other kids have it and anyway it's not as bad as it used to be :P