The problem with our Master Games List (MGL) is that you cannot have alternate names for games. So searching for SimCity 5 on Wikipedia redirects to that page you linked to, however it would yield no results on our MGL. So we include common names to assist searches, such as
F3AR. If you google SimCity 5 you will see that it's a common name, even if not official.
If we had an alternate name field that would be searchable along with the main, then I would leave 5 out of the main title, yes. The function of the name is to assist users to find the DR they are looking for, so this is the best compromise.
I might hit up Delphium about seeing if an alternate field is possible now that the PHPBB move has settled down.