So yesterday I wanted to add permissions to a resource pool on ESX 3.5 but I could not do that because the option was not there.

That looked strange because I was able to do that on other ESX server that was running version 3.0.2
Apparently for some reason VMware removed that option starting version 3.5. so the only way to add permissions is to used Virtual Centre which of course you have to buy. Can I ask why VMware did that ?