Fiction still needs some form of believablility, if Bioware wanted to go down the "humans are special" they should've at least gotten some things right.
And if Bioware wanted to make a sci-fi series, they should've gotten the sci-fi right. But they didn't, by any stretch in regards to the Asari, the physics, or any of it. Instead, the entire premise of the universe is built on fake science. The only believability you need is with regards to human biology, which again shouldn't be a problem because what Mordin says (as I recall) is that we are more genetically diverse relative to other sapient species.
As before: do you have a real life Salarian for us to compare to? If not, that shouldn't factor into the equation. You're not asking for "some believability". You're asking for one very specific instance of believability, but ignoring everything else that doesn't fit into your paradigm. This is inconsistent.
ME1 lacked a central human focused that could've easily carried on ME2/3. Sure ME1 had its share "humans are the best" moments but they weren't as prominent as they were when compared to ME2/3.
Well, ignoring that it stars a human, a special human, the first human Spectre, which is important. And that one of the central themes is all about humanity's increasing presence in the galaxy, hence why we have the ability to either cooperate with everyone else in the ending, or allow the other species to be murdered and seize power for ourselves. But note that, no matter what we do, ME1 is all about how important we are, how we've done things that no other species could ever do, and how soon we're going to ascend past everyone in virtually no time at all.
The argument would work a lot better if the ME1 conclusion didn't throw humanity in front of every other species, in terms of importance, even just in terms of competence.