Beliyal said:
I somehow got the idea that, as Desmond is the main protagonist, we'll be exploring what matters to him. So if Ezio matters to him (and his gang), we get more Ezio. Of course, we can argue that they could've thought of a way to involve someone else.
The thing is, from what i remember of the plot (it's been ages since i played any of the AC games so bare with me and my poor memory) there were all sorts of... things left behind by those alien beings, after all, don't Desmond and the Scooby Doo gang have to travel half way around the world in order to visit some sort of temple to prevent the End of Days? Something about the world going supernova?
The point is that the Apple isn't the only thing these aliens left behind when humanity had its little uprising. They have every reason to explore all corners of the earth, and assuming this brotherhood is / was a global organisation, there is no reason why Altair or Ezio or anyone else connected to Desmond's ancestry wouldn't have ties with agents across the globe. The animus might relive memories of Ezio's best mate Rupert, for example, because he may have been an important part of Ezio's life. As for explaining it, you could say that the animus pieces together the missions and exposition purely from what that person had told Ezio / whoever. It's just an idea, and it's a rough one, but i don't see why that sort of thing wouldn't be feasible.
Not to mention isn't there something like an 800 year gap between the setting of AC1 and the present day? 8 centuries is an awfully long time to be able to explore all sorts of other progenies in the Desmond family line. You can absolutely squeeze 3 or 4 other characters through all sorts of periods of history who may have been involved in the Brotherhood. After all, Altair (if i remember rightly) knocked up a Christian girl, so who's to say the same wouldn't occur numerous times in other locales? Though i will concede that, more than anything, the Animus was really a tool designed to teach Desmond how to be an Assassin rather than be a probe for finding and explaining these 'divine' artifacts.