I've never like WMI, my experience is that it has a decent performance hit that's not worth it. I'll use it if we have to. Would be nice if SNMP could be used as the default and WMI only when required.
As for WinRM, we have it set up - we are using it today with other scripts. I think our issue is we have a self signed cert from the local host, where you want a enterprise ca signed cert. I'll try that next, but as my post stated, in my opinion this is too complicated.
I feel I should be able to pick an exchange server, tell it to use AppInsight for Exchange and the deployment tool should do it's thing, setting everything up. And that's just not the case here in our experience.