This is related only to high speed file operations between many physical HDDs (copying, moving) and not between HDDs and slower destinations like FTPs or USBs.
Currently automatic queue only works when destination is on same physical HDD disregarding the fact one could copy many files to physically separate HDDs from one single source HDD. In latter case no queue jobs would be created and source HDD performance would be trashed by multiple concurrent file operations.
All that needs to be added is checking both source and destination physical drives and if there is a job currently running on any of drives in new file operation then that job should be queued to job queue related to these drives. Here is the catch, job could be queued because of only one of the drives currently being busy running file operation and there could be many jobs in the list to be executed that do not overlap with neither source nor destination of our last job to be queued -- in that case as soon as both source and destination for particular job queue are not under file operation that job should be run concurrently (since in that case we have A->B and C->D all separate physical drives not trashing each other's performance) in a separate job queue.
Current issue with manual queuing is you can't manually add job to queue that already started automatically. To answer those who say just create a button that creates copy queue: we don't really use button to copy, we use all sorts of different ways, keyboard shortcuts, menu copy paste, drag and drop, right click drag and drop with menu and so on. In these cases button doesn't help. But if I would rely on button then I would have to stop automatic queue and whole point of this is to ease the process and do it as automatic as possible.
I really love automatic queue, it's just that these days many of us have a lot of physical hdds not just partitions so approach to queues needs just a bit more sophistication.
Just as automatic queue checks destination physical drive it could check for source too and simply queue jobs automatically where either source or destination is under high speed file operation between hard disks.