Few things I have noticed so far, which are minor but can hopefully be added or answered ???
I must also say that this machine is out of this world and absolutely fantastic!
Im from vinyl but blown away by this kit, but same as anything new, there is always going to be room for tweaks adjustments and updates and i hope all are considered and implemented. 
Initially really struggling sorting my tracks.
1.On Engine prime it has stored and analysed 28,000, but i have 60,000, so why wont it allow the rest on? I have deleted re installed 5 times now its done 30,000. its 12 hours to do that each time, very stressful! Not ideal over half my collection not being on.
2. To able to add tracks to top up by usb is a MUST.
I use a pc with my collection on and not a laptop, so currently i am not happy to install my HD internally and have been attaching it to my P4 via usb then out to my PC to load new tracks.
3. The prime 4 does not tell you how many tracks you have on it anywhere, this would be nice to see ?
Do you just accept that its the amount showing in engine prime ? how can that be trusted ?
As above i need help or reasons why my whole collection wont go on ???
4 Recording level and quality.
It stores your sessions in wav, and despite me having my master at 3/4 level the quality is low and not great?
Can anyone advise where for optimum performance your master should be, your high, mid. low etc ??? Also to be able to view alter recording level quality without coming out of the screen.
5. No clock, Just thought it may have one.
I have only had my unit 1 week and loving it but above is what i have found so i need assistance help if possible.