1. With 'hosts' do you mean VMs or ESXi nodes? ESXi NODES
2. How will you provide the 'desired settings'? like the parametre that I added to VMs in the script
Like this:
Foreach ($VMHost in Get-VMHost ) { $ESXCli = Get-EsxCli -VMHost $VMHost $ESXCli.software.acceptance.Set("PartnerSupported") }
$NTPServers = "pool.ntp.org", "pool2.ntp.org" Get-VMHost | Add-VmHostNtpServer $NTPServers
3. I suspect you mean 'not set'? Yep you are right
4. What should be in that report? Juste one excel file which inclue worksheet | one for VMs - One for Node and they should include the below details in column
vcenter Node VM ParametreName OldValue NewValue
5.2 Why would there be VMs remaining to be hardened? my bad, I mean nombre of VMs hardned and number of nodes hardned
for sure output log is required, espacialy if something happen 
if you have any other suggestion, I am interested. after all I'm trying to do something that could be of use to the community.