If you prefer, it could be closed as being not constructive, as we don't know what Microsoft is using and there's no objective definition of what "professionally looking" is.
It's a safe bet to say that all professional e-mail templates are hand-crafted and thoroughly tested on various e-mail clients to ensure that they look good. And they're all not sent out via Outlook anyway.
(No, it can't import millions of contacts.)
If you wanted to ask how to stop Outlook from mangling with your previously created templates, that would—in my opinion—be a valid question to ask. But make sure you give a concrete example and provide screenshots, et cetera.
