Commander Shepard - "Shepard-Commander" as an alias. In both Mass Effect 2 and Mass Effect 3, Legion always refers to Commander Shepard in this way.
edit: Also, "Commander" and "Shepard" should be added as their own separate allies since you're referred to by both on their own countless times throughout all 3 games.
"Commander" is way too vague to be an alias. There are dozens upon dozens of games that refer to you or another character as "Commander."
I think "Shepard" as an alias would be OK though.
Shepard is fine. Commander is to vague.
Adding parts of what already appears in the title to a wiki page as an alias is redundant as the search engine already has those words attached to page once it is part of the title. The aforementioned character page already appears as a the second result when typing "Commander" and the first result when typing "Shepard.
Yeah I thought about that after I made that edit to my post, forgot to come back and edit it again.