While a number of methods have been proposed to save the state of JACK connections and restore them automatically, it's still tedious to wire up applications when you first start them up. I'd like a JACK autopatcher daemon that you could give simple rules to: "when I start up a synth, connect it to an Ardour input if it's running, else to the soundcard output, going via a JACK Rack with the same name if one's running (and starting one if it isn't)". Having an understanding of stereo pairs of channels would be especially useful.
I'd suggest jackfield as a good name for a JACK patch bay that did this sort
of thing, since it's effectively a software implementation of normalling -- I'm
surprised nobody's used it already!
I've partially implemented this as autopatch.