It seems like we should be able to use any ATAPI (or some other standard) drives, DVD, CD, CD-R, CD-RW, DVD-RAM, whatever. It's pretty clear the technology has been there for several years now. I'm starting to think it is a M$ conspiracy.
Weird that the USB zip didn't do better than the parallel one. I notice you didn't mention SCSI, they had one of those too didn't they? Maybe the SCSI version was faster.
I wouldn't want a standard based on zip disks though, after all the are still magnetic like a floppy, aren't they. That is one of the main reason I hate floppies, maybe zip disks are better about this, but floppies are so painfully unreliable. I would be afraid of zip disks for fear they could be as bad.