I got into a debate with a friend on GW. He said that Guild Wars Factions isnt considered an expansion to Guild Wars, I thought otherwise. Sooooo which one of is right him or I?
Edit: "Guild Wars Factions is a stand-alone product. Those who own Guild Wars are not required to purchase Guild Wars Factions in order to continue playing on their game account, and those who purchase Guild Wars Factions may play without purchasing Guild Wars. However, there is a strong level of interconnection between the two games that makes having them both an exceptional experience."
I understand that ^ but isnt a game based on another game considered an expansion of it?
If you want to go back to Diablo and then Diablo II same server or w/e but different games right? Yet the Diablo II is an expansion of the first one am I correct? Sooooo wouldnt GW Factions be the same like that? In my eyes it's an Expansion
, anymore people correct me if i'm wrong or let me know your opinion on this plz 

, so are we both right?