I can understand maligning ME3's narrative in its own right, but to do so while comparing it to ME2 as though the latter is really superior is a bit perplexing. ME2 pretty much goes for the episodic format, often departing from the rather scant Collector plot, padding the game with mercs perhaps about as much as ME3 may with Cerberus, and at least the latter ties in more closely to the reaper conflict. It has plenty of shining moments within those "episodes", but I find that ME2 works best in its parts than it does in its whole as far as the narrative is concerned.
Why was the collector plot scant?
Anyway, it's okay if you like ME3, but I am perplex as to why you don't think that ME2 (and ME1 too, of course) clearly had a superior narrative design.
ME2 has many very well written and interesting characters with meaningful character arcs and also numerous great and varied story arcs, which are supported by excellently designed and fleshed out locations and dialogue. Heck, even minor characters were very interesting in ME2.
I have no idea how ME3 could possibly have the better or equal narrative design with boring characters like James Vega and Steve Cortez, Cerberus the evil Sith Empire as a major story arc and fetch quests galore with badly written and boring dialogue, just to name a few things. The genophage story arc in ME3 was good and the conclusion was satisfying, the beginning of the mission on Luna too, that's about it though.
But the most confusing thing to me is the bolded. The level design? I don't believe we even played the same game, because ME2 was quite blatantly designed like an arena. Some maps were so haphazardly designed that the ground literally created cover on the fly rather than having a more natural layout to take advantage of (e.g. the raising floor panels of Purgatory). Many things were just too neat and clean, making things like rock formations and rubble seem completely unnatural. There's just no way that ME3 is at all inferior to ME2 as far as the battlefield designs are concerned. Heck, even Priority: Earth, the map many agree to look rushed, actually looks more substantial as a battlefield than the Collector base, not to mention that the enemies we face in the final stretch are strangely unimpressive.
ME3's level design is just a sequence of corridors without much variety. The levels were also quite obtuse.
But then, this kind of goes to ME2's rather odd difficulty curve, because other than the boss from Contra, the game very quickly exhausts its list of hardened, elite-level enemies very early, and then largely abandons them in the final act of the game. Like, why are there no Praetorians in the Collector Base? It's very unfortunate that Horizon should be more difficult than the Suicide Mission.
Sure, the game could have been harder.
As for choices having no meaning, I'd really like to know which choices in ME2 were more substantial than those in ME3, the latter of which has you possibly presiding over the extinction of entire races. Regardless of what people may think of the ending or the story, the decisions you make in ME3 have lasting effects on the galaxy and have very immediate effects on the characters around Shepard. You can betray allies and perhaps even shoot your friends, like how Shepard can kill Wrex, shoot the VS, shoot Mordin in the back, allow Samara to kill herself, etc.. How is that not meaningful?
Having only one ending with no choice between red/green/blue would have had lasting effects on the galaxy too. ^^
Anyway, there is no real choice in ME3, because no matter what you do in ME3 or the previous games, the outcome is the same, you just choose between red / green / blue. They change a bit depending on your war assets, but that's it.