I'm sure this was a topic when the game was new, but since I only recently got it, I really need to weigh in myself.
That was such a weird ending.
You free DC, you get the antiviral, and everyone's celebrating! And it cuts to the places you've conquered, including the place you just left. Cool, I freed them all! Something seems a bit off, but no one's reacting to that part, so who knows. But whatever. Ending cutscene, fireworks, yay!
Black Tusk now owns all of DC, even the place you just were. You never got chance to resist.
What? Who?
And no one says anything. NPC chatter just acts like we're used to fighting them. It's only in-game tutorials that tell me anything about this new situation and that's only from a gameplay perspective.
What was our reaction to the invasion in progress? When did it happen relative to me freeing the Capitol? Why didn't I fight them off before they got a foothold? What happened to the antiviral? The only one of those questions that gets answered is the last one, and it's only after I play through all of the original Invaded missions, even though that was the entire point of the Capitol mission.
The thing is, I knew about Black Tusk because I did the beta mission with them. I was waiting for them to show up all game (and caught hints of them while doing the original story). I was not expecting them to just appear unceremoniously in meanwhile shots of a cinematic without any explanation. Honestly, if I didn't know about the Black Tusk, I think I would have just assumed the cinematic was showing some generic representation of Division agents securing those locations.
What really stung is that I spent a lot of time doing all of the activities and felt really good about it, and then all of it was reset with barely an explanation. I guessed that this was a stopgap endgame until more post-launch content was added and I just read that the Black Tusk Stronghold wasn't in at launch, so that might be right.
Not to sound negative, I'm enjoying the game so far, it was just super jarring, and I think it sort of needs a bit cleaning up at this point. It's weird now that you "beat the story", only to unlock World Tiers while beating the Black Tusk story (which resolves the antiviral plot, which is arguably the actual end of the story), only to then unlock a new endgame with Targeted Loot and dynamic Invasions, as well as post-launch story.
The Black Tusk Invasion now just stands out as this complete pacing killer for both story and endgame progression.