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Wait, I'm confused. You saw a one minute, seventeen second trailer for a game and managed to see that the game was completely stripped of all complexity and failed in being nothing short of perfection? Impressive. People usually need more information than that to make their claims. Like playing the game.
You're also criticizing a trailer for appealing to the LCD in order boost sales. A trailer. Whose singular purpose is to generate buzz so that sales increase. Sure, the ME2 trailer has nothing on the ME3 trailer in the explosion counter area, but that does not mean ME2 was lacking all the things you're criticizing ME3 for allegedly having. Even ME1 had its fair share of explosions, action, and fast pace.
Also, execution is what makes great games. Not complexity, simplicity, explosions, dialogue, or story in their individual components. Explosions and lots of action does not mean something is dumbed down or simple. There are some examples floating around... like war. Yeah.
Now then, that isn't to say you are dead wrong. But at this point, to claim this is less complex or catering and will suffer for it is impossible to state. In a years time, we will see if what you said is true. However, even if it is all true, I will ask if you enjoyed the game. And that is the point.
Until then, speculation as to ME3's complexity or lack thereof is just that: Speculation.