Speaking as someone who works for a provider that administers both Smartermail and Exchange Server, I understand the confusion about aliasing, I appreciate the request to simplify it, and appreciate the part about aliases feeling more like distro groups. With that said, there are both advantages and disadvantages to how each platform handles aliases.
Exchange: On the plus side, it's easy to jump into a user profile and add an alias, such as a married name. Key in the alias and save the change. Done. On the negative side, it's more difficult to determine WHO has a particular alias. In a small office that's not a problem, but when dealing with thousands of users, it's a pain and the answer usually involves an Active Directory query or powershell script against Exchange to find the account an alias is tied to.
Smartermail: On the negative side, you can't jump into a user account and add an alias. You have to go to an administrative screen, add the alias, then manually enter the user account to associate with. Takes more effort. But on the flip side, after the alias exists, it's a lot easier to see all the aliases and their associated accounts in a single pane of glass.
Winner: In our opinion, it's pretty much a tie. You either do more work on the front-end to create, or you do more work after the fact to determine ownership and/or discover where an alias routes to. If I had to choose, I'd pick the Smartermail way of doing it because we more often run into "who has that alias already?" on Exchange, which takes a lot more time to discover.