It would be nice if there were something similar to plugin nap for instruments. To be clear, I'm not (necessarily) suggesting the ability to suspend instrument processing during moments of silence, as far as I know this simply ins't possible. (Although Digital Performer's "Pre-gen" does indeed solve this by invisibly freezing tracks behind the scenes with the flick of a swith)... I digress! .....
Basically it would be really useful if, similar to Logic, instruments that did not have any MIDI clips on them would open in a napping state until the track is selected. This allows for large templates, without instruments eating resources.
And, while you can disable/enable tracks, coming from Logic myself I have to say Apple's implementation is the smartest I've seen by far. If the track doesn't have MIDI, or is not selected it's napping, as simple as that... The moment you want to use the instrument you simply touch the track and it loads; no shortcuts required...