@Varol
Thanks for pointing out that flawed information in that path of the Exchange Deployment assistant, I will work with our EDA team to get that information corrected so that it matches the proper guidance from this blog.
The benefit to moving the External URL to point to the latest in site version of Exchange that is properly deployed is...
1. You most likely already have your environment properly sized with the currently deployed version of Exchange
2. Exchange (up to Exchange 2013) was design to properly proxy traffic as long as the external endpoint is pointing at the latest version of Exchange
3. Deploying Exchange in the proper way, meaning following our guidance to deploy Exchange 2013 into an existing 2010 environment will be much less impactful than attempting to work around the designed coexistence logic we have in product
4. In addition, there are many customers that will end up keeping a good portion of users on-premises, in that case they may want to move some of the users to Exchange 2013 on-premises. If you deployed correctly from the beginning there is no extra changes
that would need to take place... you just move mailboxes
5. All of the validation that we do for Hybrid features is done against on-premises environments that are deployed in the expected way.
Again, thanks for the comments...
-Tim