This feature was extremely useful in VMWare server. I would set the drive to be very very large and then monitor the free space on the host computer. Once it got low then I knew it was time to move the VMWare guest or upgrade the underlying hardware.
This option appears GONE in VMWare ESXi which unfortunately makes me pause on continuing to use it.
Is there any hope this feature will be included again at some point?
You can create thin disks. I'm not sure if the RCLI supports it yet, but at the console you can create a thin disk with the command
vmkfstools -c 10G -d thin TEST.vmdk
If you look at the file, it will be displayed as 10 GB in size (i.e. with ls at the console or with the datastore browser), but if you run df -h at the console before and after you create the file, you'll see that the flat.vmdk file has not really used 10 GB. Thin disk can create performance problems, so you should be careful of when and how often you use them.