I never had a problem with the kid. It was always clear to me that he was a cipher that represented humanity as a whole, and Shepard's subconscious feelings of anxiety and guilt that people are dying and there's nothing she can do to stop it. As well as the growing fear that she can't actually save them.
See, that's where ME3 diverges from the previous games. It's giving us a Shepard who is now completely out of our control when it comes to deciding her greater motivation. One of the big choices you can make in the first Mass Effect game was actually putting humanity first above all the other races and thus giving humanity more influence in shaping the galaxy. In Mass Effect 2, you can actually support Cerberus by working towards all their objectives and even giving them the means to not only fight the Reapers, but solidify TIM's goal of "Human Dominance" of the galaxy. While I still hate Shepard's line "Human dominance, or Cerberus?" as if to imply that human dominance is an ok thing to stride for, Shepard nonetheless can tell everyone in her group that they're not fighting for humanity, they're fighting for the whole galaxy.
With Mass Effect 3 Shepard's motivation is all about retaking Earth and the story pulls a lot of dumb things in order to justify this motivation. For one thing we have the child I spoke of earlier, the other is leaving Anderson on Earth to give you a motivation to come back, and finally, lowering Shepard's IQ to 27. I'm serious. Note this exchange in the beginning.
Admiral: Than how do we spot them?
Shepard: Stop them? This isn't about strategy or tactics. This is about survival. The Reapers are more advanced than we are. More powerful, more intelligent. They don't fear us and they'll never take pity on us.
So far so good. One Reaper was enough to hold off an entire fleet at the Citadel, where as this is multiple Reapers ready to descend upon us. The number one thing we should be doing is not putting all our forces where they're going to attack, but withdraw and regroup to plan something out later. That's what I get from Shepard's response. Than we get this.
Admiral: What do we do?
Shepard: The only thing we can do. We fight or we die.
Ok. Shepard not only contradicted her previous statement about survival, she also contradicted herself in that very statement (Fight or die are two things, not one). When it comes to "fighting", you actually need strategy and tactics in order to fight at all. So the Reapers have arrived and are now destroying everything, so Shepard, who possibly has the love of her life somewhere out there, whether it be human or alien, has this exchange with Anderson.
Anderson: We've got to get to the citadel.
Shepard: The Citadel? The fight is here!
Anderson: It will be everywhere soon enough. You told me that.
Goddangit. This is NOT MY SHEPARD! If it was my Shepard, these lines would be in complete reverse. If this was the pro-human/Cerberus Shepard from the last two games, the exchange would make a lot more sense. But the Shepard I played isn't that kind of Shepard. She knows that the Reapers are going to be after everyone, she knows that they're going to attack many systems at once and she sure as fudge wouldn't leave her friends or love interest in the dark just so she can fight on Earth, a planet that so far in this series has had zero relevance to anything. The Moon got more exposure than Earth did.
So what's so wrong with Shepard caring about the fate of Earth?
The 67% chance that Shepard's not
from Earth?
Yep. Two out of three origins for Shepard don't even have Earth as their home, and the one origin that features Shepard coming from Earth has them join the Alliance to, and I'm not kidding, get away from Earth because it was a bad place.
Earthborn: You were an orphan raised on the streets of the great megatropolises covering Earth. You escaped the life of petty crime and underworld gangs by enlisting with the Alliance military when you turned eighteen.
Another fun fact, having a Shepard who's from Earth is the least "Paragon" Shepard in all the profiles. So if you want to make your Shepard a total renegade, you have to be from Earth!
This is what I'm talking about when the game literally goes out of it's way to retcon the previous games in order to get the player to care about something that was never a factor in any of the previous games. The only thing Earth should have been was a place that the Reapers attacked. So what if they took it? It's not like Earth is the only Earth like planet with breathable air and vegetation that we can all move to. There are a crap ton of human colonies out there in space, even a totally human run planet that stores a lot of historical Earth artifacts.