I haven't seen the ending yet, but if the main complaint about the ending is that "nothing you did mattered in the end" isn't that true of... well, the entire series?
No matter what you do, you still stop Sovereign from destroying the Citadel.
No matter what you do, you still destroy the Collectors.
Heck, look at Dragon Age. No matter what you do, you still stop the Archdemon.
You can change DETAILS of that, I guess, but at the end of the day you're still heading towards the same result no matter how you play it.
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TheRock ~ Slow dramatic zoom-pan. Doesn't phase the hooded man.
"You have issues." - MWC. Pot. Kettle.