ME3's 'teamwork' is a joke, because the game simply introduces entirely artificial 'only this guy can save the day!' situations, when there should be dozens of better solutions. Its just as much a symptom of the bad writing as the 'Shepard punches out Cthulu because he's brave and incredible and has a really strong punch' kind of nonsense. The only difference each time is who gets to be the guy bellowing 'I'll throw a barrel at them!' or 'I'll rig up the superconducting ocilliating vibrometric spunkometer device - all of you RUNNN!'
Whoever is the one currently saying or doing this stuff (and it is usually Shepard) doesn't make the situations themselves any less silly or contrived. Its still the characters doing counter intuitive things purely because it looked cooler to do it that way (and often at the expense of using abilities that you have which *would* have made sense to use). I.e the game is forever powering people up to perform outrageous acts and powering people down to stop them handling problems they should easily be able to manage, just to fit each situation and set up the current 'X Character to the rescue'. It felt massively contrived, and the game does it non-stop.
Take that Eva Corey bit for example.
Shepard: 'Oh no, she's getting away! Let's run after her and stop her'.
Liara: 'Well... okay, but couldn't I just use Stasis...? Or Singularity?... or Pull? Or couldn't you just use that fancy Biotic Charge thing - it works against everyone else?'
And upon reaching the pad, Shepard decides the best way to deal with the charging Dr Eva is to try shooting her with a pistol. This is despite having any number of better alternatives from Overloads to Biotic Charges, and having just seen Ashley try the same thing and fail. Given that Ashley's whole thing is that she is an extremely accurate and fast shot - a weapons master. So does Shepard try another approach? Of course not - because the power of being the Captain means that when she tries it, it just works!
The game is an endless cycle of 'Its this person's time to shine!', several bouts of Cutscene Power to the Max (Kai Leng, Jacob, Jack etc) and typically they get just that 1 moment. You mentioned some for the characters. Now name another one for any of them. They get one moment (typcially when they get recruited) and that's it. And as for Shepard I'm not saying I don't want to see my hero do heroic stuff - but everything in moderation, yeah? I don't need to see Shepard saving the galaxy by making Harbinger tap out in a Submission match on top of the Crucible, and that's exactly the kind of comic book nonsense I felt he/she was always doing in that game. So many times, directing her companions to flee or hang back whilst she went solo to 'do something awesome'. And that's when she wasn't crashing other people's big moments, just to get even more screen time (leaping on screen to shout NOOOO! as Tarquin dies, undercutting Liara's rescue on Thessia by immediately racing after Kai Leng's shuttle firing a pistol like every good 80's hero should etc etc). Shepard simply gets so many of these silly 'Hit the Hero button' moments, that along with the non-stop ego massaging from everyone, it just feels like swallowing a whole jar of honey. Nice at first, but quickly very sickly.
I want my character to feel like a person, not some superhero who is forever leaping tall planets in a single bound. In Mass Effect 1, I felt like a hero, but I felt like a person. In ME2 and ME3, I just feel like some Superhero cliche with large amounts of 'Space Messiah' slathered over the top for good measure.
I don't want this to become the ME3 thread either. I'm just pointing out that we need to preserve absolutely nothing about the writing from ME3. That kind of thing we don't need. Don't keep letting the main character hog all the spotlight, in the way that Star Trek would always allow the Captain to completely overshadow and usurp the various crew member's jobs. Always be asking yourself 'What are the various party members good at, and is there a way we can use that in a given scenario, should they be present?'
Because you have silly scenarios where (to briefly return to ME3 as its fresh in my mind at the moment):
Tarquin Victus is allowed to disarm the bomb, despite the fact that Shepard herself can be an Engineer and presumably much better trained for that sort of thing. That's right - I wouldn't mind Shepard taking the honours there, because (if she's an Engineer) it makes much more sense for her to do it. But either of Garrus and particularly EDI, if you brought her would also be far more appropriate. I brought EDI along, and was screaming 'WHY DON"T WE JUST LET HER DO IT, YOU MORONS!' But no, instead our tech expert with superb reaction time and ability to directly interface with the system... is sent out to gun down Cerberus goons. Instead of sending the soldiers to do it. Same deal when you get people to fix AA turrets and the like, despite the fact that you might be the most qualified person there to do it.
Or you have the Seeker Swarm chamber from ME2 where Shepard needs a Biotic specialist to create that barrier - and never considers herself as a possibility, nor does anyone else. This is despite the fact that you can be an Adept, Jack and Samara could be dead by then, and you can choose someone like Jacob (whose abilties are not to be sneered at, but clearly would be an inferior choice to an Adept Shepard).
The point I'm making is that ME3 is lots and lots and lots of small tightly controlled, and often extremely far fetched excuses to show a character (usually Shepard) doing some equivalent of standing on top of a burning car in a vest, holding a minigun blazing away as a helicopter explodes in slow motion behind them. Its just a long sequence of badly set up and extremely artificial money shots, that usually make no narrative sense if you consider all the things that were much more likely to happen in that situation. That's why it fails as an RPG for me, and is more akin to a simple single player action game, popcorn muncher.
And this will be my final word on this, because I realize this has hi-jacked the thread, but the ending does not disprove the power fantasy theory. You become Space Jesus and send your soul out fo unite everyone, you become Space Mecha God/Satan and leads the armies of Space Demons on a large reconstruction effort to rebuild the galaxy or you beat all the bad guys and become the savior of everyone - and survive. I mean you literally hold the power to create and destroy life (potentially for everyone and everything) in *your* hands. If that's not a power fantasy, then how much power do you require?! Because TIM has nothing on you, if that's still not enough for you!