Your choices didn't matter by the end?

ME3 was a pretty poor game(IMHO), with some sections of quality, notably tuchanka, followed by an utter trainwreck of a finish. If it wasn’t for the fact I had built so much affection for the series and character based on first 2 games I wouldn’t have finished it or replayed it.

But here we’re limiting it to the notion of choice in the ending and not the myriad of issues outside of those narrow parameters
Well we better start by talking about EMS/GR, It’s a generic, heavy handed unwieldy system to try and fashion choice through. So unlike Me2 where you have a specific choice leading to a result(don’t upgrade shields – death), this approach means all those choices get dumped in a big pot and stewed together and they lose their individuality to come up with a magic number. Unlike say DAO where if you recruit golems you can fight alongside those golems. Some consequences appear visually but they are passive. It’s just a bad way to make choices feel consequential.

Then there’s the fact the mission feels completely on the rails. The mission should be the main point(alongside the aftermath), it’s the culmination of the journey. There’s no reason they couldn’t have developed and improved upon the wonderful notion of making decisions and assigning tasks that the suicide mission introduced. In ME2 there’s a sense of agency, assigning squad or degree of preparedness has visceral, personal results. Here it’s just so linear(with exception of Steve’s fate which is a flashback to how things were handled in ME2)

Since you brought it up I found whole camp scene not particularly great. ME2 squad including LI’s are reduced to video messages rather than being active assets. My LI told me to finish it and find her, pity that’s not a choice. All feels terribly staged eye of the storm moment because they know they haven’t bothered with any feels later.

If you include EC, the notion of choice in the final battle is eroded further by the Normandy landing and taking squad away. No choice to get reinforcements, no shep must stumble on to the set in stone encounter with Harbinger on his own whilst Normandy flies off to meet its mostly linear let’s flee and crash on Gilligan’s island.

I’m going to be corralled in slow motion section, compulsory shooting of Anderson. A moment of respite as your choices with TIM finally potentially give you a small branch in the road.
Then it’s back into a linear path to the joke decision chamber where it turns out you can’t succeed without permission of the reapers. That certainly helps emphasise the sense of nothing you have done mattered. That’s a major robbing of agency, where your choices have boiled down to failure. You could have the highest EMS in the universe and you couldn’t succeed unless the enemy uplifts you.

Once you are uplifted the worst sort of choice rears its ugly head. Time for an ambush of all the consequences of using the superweapon because the last second is a good time for that! It would be like Mordin telling you genophage cure will kill all Asari just as he’s about to enter the cure. Why didn’t we have this discussion earlier. Why has control been limited to TIM and not seriously debated as an option. Oh wait let’s introduce a random new option, that bears more than a passing similarity to Saren’s. Good thing there’s a trustworthy source to spoon feed you this nonsense!

Not only as I’ve outlined are these terribly introduced, unbalanced, from an untrustworthy source but they turn out to boil down to 3 flavours of committing suicide. Personal choice has gone out of the window. Unlike ME2 or DAO there’s not a choice that delivers upon the notion of survival of protagonist alongside one that delivers their death. In DAO you can be selfless, selfish and reckless. The closest here is an abrupt detached joke breath scene and the chance to be trolled by devs with maybe ‘it’s a final breath’

Pre EC there’s no real epilogue unless you consider creepy grandpa it. Post EC there’s a slapdash effort, that's still short of even DAO’s interactive post ending game play and slides and texts and that’s in a game with a simpler ending involving killing an archdemon, not murder races/genetically rape people/install killbots as overlords.

So in summary, the effect of previous choices and live choices are either absent or utterly terribly implemented

How many times can I "like" this?

Not totally the case.  For example, the Paragon/Renegade leaning also plays a bit of a role.  As you've said many times, it determines whether or not Control or Destroy are offered as the singular choices below 1750 EMS.  It also determines whether you get the "one who could save the many" or the "one who could lead the many" speech if the player selects control at any EMS level.  Also, if you do effect a peace between the geth and quarians and select synthesis, the quarians, without their masks, are shown talking with geth in the ending slides.

PLEASE NOTE:  I'm not saying it was perfectly done... or even all that well done.  Just saying that the ending wasn't ONLY based on the EMS number.

Nothing done in the game really impacts the ending choices in ME1.  Saren always dies but before he does the game looks at a number (charm/intimidate points) and decides whether or not you have to fight him... and that's all it decides.  You can choose to save or kill the council regardless of leaning or anything you've done to that point... but really only the speech the council, Udina, or Anderson gives you will change depending on whether you're more paragon or renegade; and the background music will change.  In the end, you get a red background or a blue one behind Shepard.

What gets imported into ME2 isn't even very consistent... I've done playthroughs where I've gotten all the Renegade talk and music at the end of ME1... and the import still says I followed the "paragon path."  I can even arbitrarily change who I appointed as councillor.

ETA:  ... and some of the Catalyst's offering dialogue does change depending on whether or not Shepard is paragon or renegade.  For example (both high EMS):

To directly address the OP - I agree with you.

This is true. But there's still a lot of meaning you can bring into this yourself, to make it work. As a game, it could have been much better. Bit you're still your own "movie director" of sorts.. you still give things unique flavor by how you reached point A to B - and with whom.

Well, I'm here to tell you that your opinion matters as well. Bring something to it yourself  Not that you don't do that -- I think you do. But I'll repeat it.

It'd be nice to get feedback and consequence to a lot of these choices, and I think they got lazy (and/or rushed), but there's still meaning in your own values and favorite characters. You don't need anyone else to tell you that. All of these things to me are like symbols to play around with and configure your story around. I don't necessarily need detailed narrative. There's still narrative there.. you just have to read between the lines.

Choices do matter.

Are people really attempting to use War Assets as legitimate argument why choices don't matter? The act of getting war assists is a choice in and of it self.

ME3 default playthrough doesn't agree.

I think there are two differents aspects of this problem.

Overall, the statement that your choices don't matter is completely false. There's a great deal of continuity created by past decisions at many points in the game, apparent in dialogue changes, cutscene changes (for instance in the EC), NPC changes, etc. etc.

The problem that created this impression is that no decision affected the final mission and the Catalyst conversation at all. We don't see different fleets showing up depending on our decision at Rannoch. We can't speak with the Catalyst about making peace on Rannoch, which is a very relevant outcome considering the problem it asserts. As opposed to ME2's final mission, we can't make any decision about how ME3's final mission goes. We have visible differences in outcomes before this mission, and we have visible differences after it in the EC epilogues, but here, where it matters most and where we would want, need it most, things are completely on rails. We are at the whim of the "AI god" that controls the Reapers, which is about the worst possible place to be at the time it matters most, and nothing we did before could affect that in any way.

Technically, it is comparable to not being able to affect the final fight of ME2 with any decision. We couldn't do that either, we always had that encounter and we always had to fight there, but the difference is that we weren't at the whim of the enemy's leader so it was ok, and people put up with it.

I think all of the problems with the ending - as opposed to other major problems affecting the game as a whole - eventually come down to this: the enemy leader, not we, had complete agency in the end, and we had to implement one of its solutions or let the galaxy die. It was the ultimate blackmail, and I think we could reasonably expect things not to be like that. Not having a choice there, or not seeing effects dependent on past choices  - as not having a choice in so many other final encounters in many, many storytelling games - would not have mattered at all had we not been forced to act according to the enemy leader's plans.

I agree... and think the cause was more a continually changing of the guard that inevitably brought about some mid-course changes.  New people bring in new ideas and, in trying to incorporate those, the old ideas became weakened and sometimes outright shunted aside in the process.