I thought it would be more correct if I create this posting above as an idea here, pardon for the repetition.
I am a happy user of Workstation for over a decade, since days of I think version 4 workstation.
Recently, began to use Tails Linux https://tails.boum.org/ and of course it works with Workstation 12 pro.
But I had been only booting up Tails using ISO image live CD mode. In this mode it can not create a persistent file to store some info or settings. As result I am using vmware snapshots to store.
Tails only creates persistence file to store info when it boots up using USB thumb drive. Yes, I had been able to use USB thumb drive and booted up in EFI BIOS mode in vmware too. But I have to physically plug in a USB thumb drive too.
It is kind of good if VMware will allow a vmdk file virtual disk - same as those we connected via SATA / SCSI, to be also simulated to be (HOT) plugged into VMs. Then in this case it will become very convenient.
I think for more than just Tails purpose, if VMware could hot-plug VMDK disks as USB device, it serves a whole lot of useful functions for test / development and powerful usages.
There are physical USB HDD SSD and there are physical USB thumb drives. I suppose VMDK files can simulate them, but I can be ignorant or wrong.
My suggestion is to have essentially thumb drives / SDcards / MicroSD cards simulated by VMware using a VMDK like file / files, this will be a new dimension of simulation that is still a lacking now.
Thanks & regards