If you need to remotely shutdown an ESXi Server, what you could do is enable the "non-supported" mode which allows you to SSH to the ESXi Server. You can quickly shutdown all Virtual Machines and then power down the host, assuming you have enough power/time to run these tasks.

You might also look at using the RCLI to remotely connect which does not require you to enable the "non-supported" mode and power down VM's and the host.

Correct. I believe that's where VMware is going with VIMA, it's the Service Console without being tied to the hypervisor. You can manage multiple ESX and ESXi Server and utilize either RCLI or VI Perl Toolkit to manage your Host/Virtual Machines. I think someone had mentioned that 3rd party companies are working on agents that can be installed on VIMA which can then query the host or virtual machines. The RCLI just needs to get faster in returning the results and provide the same level of toolsets, if not more than the traditional Service Console before it really becomes main stream.