It isn't really. You still knew that you pretty much saved the galaxy at that point.
You knew about the Reapers and you eventually found out that they were behind the Collectors and were building a new Reaper that would be used for who knows what.
Plus you defeated an entire army of minions on the way and blew up their base, and their ship, and the Reaper, and you did all of that with a small team against impossible odds.
In some sense, your role in Mass Effect 2 was 'bigger' than in Mass Effect 3.
Add to this:
Neverwinter Nights - You saved the world.
KotOR - You saved the galaxy.
Jade Empire - You saved the Empire.
Dragon Age - You saved the world.
Mass Effect - You saved the galaxy.
The same probably applies to Baldur's Gate though I haven't played it.
Even if you take similar games by other people, like Bethesda or Obsidian, you always end up saving the world in some manner.
So if you like Bioware games or modern RPGs in general, what are the chances that this element of changing/saving/destroying the world has something to do with it? Perhaps even through proxy?
It certainly does for me, not merely because of the ego stroking nature of such narratives, though that is part of the appeal, but also because of the grand mysteries that come with threats of momentous magnitude.
I feel that there has to be some earth-shattering thing you ought to find out.
Take the Rakatan Star Forge from KotOR for example or the Protheans and Reapers of Mass Effect. Those were the things that kept you glued to the screen.
Your quesiton to me was: "In other words, do you think you would have felt the same if your decisions had affected only a small corner of the world independent of the larger narrative?"
My response was Mass Effect 2, because it was not a global conflict. As I stated before, nobody besides Cerberus, the Council, and a few others even knew of the threat. Much like Knights of the Old Republic II: The Sith Lords, while your decisions made have had significant impact on the galaxy, nobody knew the galaxy was on the verge of destruction to start. So in essense, these conflicts really only affected a few, of which they were directed at, while the rest of the populace was ignorant of these catastrophic events.
Part of the beauty of this story-telling approach is it's not the traditional global-scale offensive that you saw in ME1 or ME3. It's a much more personal and darker tale, of which being the hero doesn't mean you will be recognized or even praised. It's much more of a anti-hero theme, similar to The Witcher, where you play a pivotal role, but you may not be remembered or given the credit you are deserved.
We'll ultimately just have to agree to disagree, but I don't need to personally be a celebrity or the center of the galaxy in order for the story to be compelling and interesting. What makes the experience memorable for me are difficult choices and meeting companions and people that I become invested in and care about. As Kreia said in KotOR II, "It's not the destination that matters. It's the journey."