If anyone out there is curious, here's the official response from VMware on this question:
Thank you for your Support Request.
Unfortunately, we don't have a way to set the policy globally in 5.1. The KB does provide the commands to set the queue for the device. You can script the configuration and run the script on each host. Other than that, we currently don't have a way to mass deploy that configuration to all hosts or to make the setting global again.
Please let me know if this answers your question or if I may close this case.
Technical Support Engineer
Global Support Services, VMware Inc.
Quick update on the above posts...
Looks like you can now set these values globally if you apply Patch Release ESXi510-201212001:
There are multiple patches in this release, but the one that changes this behavior is included:
PR926287: ESXi 5.1 does not provide advanced parameters QFullSampleSize and QFullThreshold which are required to enable adaptive queue depth algorithm. This patch resolves the issue by providing the advanced parameters to set the values globally.
Note: You can also use the esxcli command to set these values per device. If both the options (esxcli and advanced parameters) are used, the per device values take precedence.
So there you go. Apply the patch to your hosts and you should be able to set the value as you have in the past.
Nice! Thanks for sharing!