The newest builds of Outlook 2016 have a new, simplified account dialog. It’s definitely simple and easy to use (although a little slow IMHO). Just type in your email address and wait for Outlook to find the account and ask for your password. It’s a couple more steps if you want to or need to create the account manually; you need to enter your email address, choose manual setup, wait for Outlook to look for the account information then choose the account type you want to create.
Honestly, in the end it’s just a prettier version of the old dialog, but some people prefer the older, familiar dialog. I think the old dialog is faster, as you don't need to wait for Outlook to search for accounts.
You can turn off the simplified version and revert to the older add account dialog by editing the registry. While this is not necessary for most situations, it is necessary to set this key if you want to create a send-only account. This will allow you to create an account with "mail" as the incoming server name and the actual SMTP server name in outgoing.
As always, if the keys don’t exist, you’ll need to create them.
HKEY_CURRENT_USER\SOFTWARE\Policies\Microsoft\Office\16.0\Outlook\setup DWORD: DisableOffice365SimplifiedAccountCreation Value: 1
If you don't want to edit the registry, I have this ready-to-use reg file available:
Disable Office 365 Simplified Account Creation