Shepard cares a lot more about people than places.
How does that explain the scene when Anderson suggest getting the help from the council and Shepard responds with this?
Shepard: The Council? The fight is here!
Because evidently, that's where 80% of the Reapers are. Shepard wasn't aware at the time that the Reapers had hit Palaven -- and even then, they had sent a somewhat smaller force to do that job. Likewise, Sur'kesh and Thessia didn't get hit until WEEKS later; as Udina himself put it at the Citadel "Earth is the first council world hit. By all reports, it bears the brunt of the assault."
Which is probably why we never even got to SEE Earth until Mass Effect 3. It's a boring little planet that is otherwise strategically insignificant and only became important when the Reapers used it as their forward command post at the start of the extinction cycle (thus it's slightly less important than Kar'shan, but the Batarians suck and nobody likes them so nobody's gonna rally to save their crappy little planet).
Which again doesn't make any sense when there is a much better command post for their invasion at the Citadel. You know? The one place the Reapers designed to be a TRAP for all space fairing civilizations.
The whole point of which was the Citadel was supposed to act as a control node for the mass relay network, and conquering it would cripple the network and force everyone to fight the reapers on their own, planet by planet. For whatever reason, the Reapers were unable to do it this time (even after they took over the Citadel) so obviously somebody on the Council (probably Udina/Anderson) took steps to close that particular loophole. Considering that entire aspect of the Reapers' strategy is contingent on nobody knowing that it even exists, it probably wasn't that hard to fix.
Why hit only humans when they can hit everyone at once, EVEN humans?
Because a human vessel with a mostly-human crew totally screwed up their battle plans on three separate occasions and even managed to kill one of them. So either the Reapers are scared of humans and want to make sure to overwhelm them so they can't pull some other trick out of their sleeve (which they wound up doing anyway) or they're really PISSED OFF at the humans and want to make sure they get hit the hardest of everyone. Either option is fits Harbinger's final threat from ME2:
Human, you've changed nothing. Your species has the attention of those infinitely your greater. That which you know as Reapers are your salvation through destruction.
It's probably a combination of both: the Reapers have noticed the tendency of humans to throw monkey wrenches into their plans, which has them both nervous and angry.
Shooter Gameplay and graphic wise, I can kind of agree. But in terms of a consistent storyline, the scale of the locations, the variety of game play, the consequences of choices, the overall atmosphere and themes, I still consider the first Mass Effect game to be a much more enjoyable experience. Mass Effect actually made me feel like I was a part of the universe it was set in, rather than the universe revolving around me.
That's just because the levels were smaller. There's something to be said for having to land in a random spot on a planet and then drive fifty miles across rugged terrain just to get to where you're supposed to be for the firefight. The Bioware team made the choice to eliminate all that and just have the shuttle drop you off at the mission area; it was a calculated decision that wasn't popular with everyone.
OTOH, they kind of made up for it with a uniquely nonlinear storyline. You have to visit a dozen different places and do a dozen different things in no particular order, there's a zillion side missions and a zillion random things you can do for extra money/power/prestige/gear. Unlike ME1 which was relatively short and to the point Spec Ops mission, ME2 was more of a six-month gig as a galaxy-hopping mercenary. If not for the fact that you're ultimately motivated by a singular Captain Ahab grudge against the Collectors, you could just as easily take this crew you've put together and change your name to "Dread Pirate Shepard."