Again - Active Directory Management Pack - AD MP - SCOM 2012R2 - AD 2012R2 - Action / RunAs Account permissions

Question

Hi,
after reading many Posts and Blogs i came to the conclusion that it is still unclear to me what is needed to Monitor Active Directory successfully and what is the securest way configuring the RunAs or Action Account. I hope the experts here can make a clear
Statement to answer the question for all time ;-)
1. Action Account:
Here is described what permissions and rights are needed to use a low-privileged account:
https://technet.microsoft.com/en-us/library/hh212808.aspx
Now you might say: that was asked and answered so many times..you are right, but the answer was from run as "local System" to "you Need local admin". So also the AD MP documentation still says you Need a local Admin account.
here are other references which says you Need local admin rights:
http://micloud.azurewebsites.net//2014/02/26/scom-agent-grayed-out-when-trying-to-monitor-domain-controllers/
Even Kevin Holman says here
https://social.technet.microsoft.com/Forums/systemcenter/en-US/2a0e5a2b-a3d9-42d4-8474-9f690007caa0/opsmgrlatency-cn-gets-auto-created-in-domain-not-configuration:
"Basically - if your domain controllers are running as local system default agent action account, in most cases you will not need to ever set up any replication monitoring run-as accounts.... as local system on a DC has all the rights necessary. 
(in most cases).
"Simple questions: Is this really enought to Monitor every aspect of an ActiveDirectory Domain and Domain Controller using a low privilege account the the permissions in the article? Or is using local System better? Is there a difference when
using SCOM2012R2 with the new Agent? Most documentation referes to SCOM2007(except the replication Monitoring where it is clear that other permissions are needed:
http://blogs.technet.com/b/jimmyharper/archive/2009/05/20/configuring-or-disabling-replication-monitoring-in-the-active-directory-management-pack.aspx )

Answer 1

The MP guide is not really clear about it. The only thing they are clear about is whenever you want to use client monitoring. In those situations low privileged will not work.
For each of the client-side monitoring scripts to run successfully, the
Action Account must be a member of the Administrators group on both the computer
on which the client management pack is running and the domain controller that is being monitored. The
Action Account must also be a member of the
Operations Manager Administrators group, which is configured through the Operations console in so that all the scripts that are configured on the Root Management Server can run properly
Both a local system and domain admin are a risk. If someone loads a malicious management pack that makes changes to the AD services you are screwed. The local system has unrestricted access to local resources including domain services.
The only reason I don't want a domain admin account in SCOM is that you have an additional layer where the password potentially could be retrieved. That's not the case with a local system account. But the risks are the same.
See: https://msdn.microsoft.com/en-us/library/ms677973%28v=vs.85%29.aspx
But this not an answer to your question. :-)