I'd like to think I've done a fair bit with single image clusters, now supporting around 160 single image clusters, but theres a number of points that really bug me at present...
1. No linked single image:
Of all our single image clusters, they all use the same hardware with the same addons and components, so it would be really beneficial to link to a common image (much like a baseline), rather than set each of my 160 single image clusters individually - no matter how I do it, I need to either script to update 160 clusters (which is not as easy as it sounds), or manually update 1 by 1.

2. VMware tools is not a base image item:
You would think out of all the components to add to the single image main screen, the esxi version should be the first item as expected, but the vmtools version should be the next item as theres often security updates for it - having to dig through the components list to find such a key component seems really short sighted to me.

3. The firmware version is not showing in parent folder summaries:
It might be minor, but the summary page in the parent folder tree does not show the firmware version - this is really beneficial for quick checks to see which single images need updating, while there is no linked single image.

I'm sure theres countless others to add, but after really good help from the Denver support team, they have managed to resolve most of my other issues...