Just replaying Mass Effect 2, and whilst I enjoy this game, it does lack focus.
For example, did you know this game only really has 6 main missions? You've got the Prologue, Freedom's Progress, Horizon, the Collector Ship, the Reaper IFF, and then the Suicide Mission.
The vast majority of the game is comprised of either squadmate recruitment missions, or loyalty missions; neither of which really have much to do with either the Reapers, or the Collectors.
Then, when you also take into account that ME3 basically did nothing with a couple of the plot threads that ME2 left open, it really feels like a major narrative detour, sandwiched in between the "OMG, the Reapers are coming/here!" storylines of the first and last game.
I can appreciate that this is definitely more of a character-driven story than the other two games, but when you are stuck in Act 2, doing little more than back-to-back loyalty missions for hours, it really does make me desperate to get to Mass Effect 3.