I was reading a portion in the "Whats new" located here technet.microsoft.com/.../dn531078.aspx;that I seemed to have missed previously. It mentions hybrid server side sync setup with crm on-prem and exchange online.

https://technet.microsoft.com/en-us/library/mt703269.aspx

I've got the email router now, would it be beneficial to set this hybrid set up? In the instructions it looks like there are only a couple commandlets used on Azure AD, is Azure AD really required? (we are not using as we have on prem AD)