User blog comment:James12708/Bioware Hasn't written themselves into a corner/@comment-4950455-20121109062047/@comment-1679409-20121109084915

Well, I don't think retconning would be completely necessary. I think they could do what they did with ME's effect on ME2 in that the actual effect you experience directly are minor. They might affect things in the way of (comparatively) slight dialogue changes (e.g., your conversation with Anderson), allow/disallowing fairly brief encounters (think the rachni's asari emissary), or change who you meet though major outcomes are similar (e.g., Ashley or Kaidan on Horizon, Mordin or Padok Wiks in ME3).

Of course, minimizing the actual experienced effects annoyed me about ME2 and will no doubt annoy others if they go that route. Plus, this would mean limiting the roles of some popular races and characters. For example, the quarians can be virtually extinct while the geth can be entirely extinct, which would limit or eliminate the roles of those races would play in a future game. You might run into a random geth that survived if you picked the quarians and didn't pick destroy, but how big of a role could it play if many files will have the geth being destroyed. Similarly, every squadmate can die in at least one of the games, which would limit their roles even in save files in which they survive.

(Sorry if this proves incoherent. The melatonin is kicking in.)