I'm relatively new to Premiere, and am still working up my workflow…
On FCP7 (and editing HD rather than 4K), the final steps were:
1. Export a ProRes 422 HQ final. This took about 15 minutes. I'd grab a cup of coffee.
2. Run a command-line script that created all the final assets using FFMPEG. This took 2-4 hours.
Now that I'm on Premiere, and editing 4K, step 1 takes hours upon hours. That's not surprising in itself, but it means that there's downtime from when #1 completes and I can kick off #2.
So, and I realize this is a long-shot, is there a way of initiating an action (AppleScript, etc.) once an export completes? It could potentially save quite a bit of end-to-end time, since the system doesn't have to wait until I notice step 1 is done and I can kick off step 2.
Not exactly what you're looking for, but this might help some. If you export via Adobe Media Encoder, you can turn on the preference to "play chime when finished encoding". That way you will be alerted when the export finishes.