Also liking the simplicity, and I think it might be a nice feature to keep
the possiblity to save:
* the studio
* the room
* the project

Perhaps the user could "tagg" each app as what function it has/what its being used for,
and then allow the saving of all apps with the same "tagg" to a file, for re-use?

EG:
-name-       -tag-
Qsynth       piano
JackRack          piano       (well, its reverb really)
calf                     piano       ( compressor)

and then save tagg piano, and you can reload the same programs?

It does substantially add to complexity I'm aware, but I like the concept of being able to save subsets of programs and reload them seperatly from the exact project that they were created in.
It seems a really usefuly feature, get a brilliant piano sound, double click the file, and your done & playing!

Thats looking from a users point of view. I appreciate that including these features in JACK might not be the way to go, as its not "core" jack functionality.

Thought I'd share this idea.. Cheers -Harry