Subverting expectations isn't the same thing as disappointing people, which seems to be the new trend in popular entertainment. Finding a razor blade in my salad is subverting my expectations, but isn't exactly something I'm going to applaud you for.
This game took a risk betting everything, every element of its narrative, that it could make you sympathize with Abby and care about her as much as the first game did with Joel. Abby's half of the game is less dark - more about stopping people from being harmed rather than inflicting harm upon them. She plays fetch with dogs instead of killing them, she gets to grow and change her outlook on the Scars and save children. She even has the better gameplay sections, with more combat and better pacing.
But even with all of that in my case it was a complete failure. Abby never did anything that redeemed her murder of Joel in my eyes, and the devs could only come up with pairing her with a cute kid and hope that the first game's magic would rub off on her.
Forgiving someone who loved you and you loved back over a lie is a far cry different from forgiving someone you never knew who showed up one day and tortured someone you loved to death, destroyed your entire world and who never once sought forgiveness or showed remorse. All the epilogue does is punish Ellie even further, since Dina leaves her along with the baby and Ellie loses two of her fingers, making her unable to play guitar, her only remaining connection to Joel.
I understand the game's message that revenge is bad, but it really only comes across as bad when Ellie is the one seeking it. Abby got her vengeance, it was practically served up to her on a silver plate; she was never once sorry for it and wasn't punished for it to the same degree, and will now get to have a life bonding with Lev just like Ellie would have had with Joel if not for her. To me, Abby is a fundamentally horrible person that did nothing to earn mercy from Ellie, and certainly didn't earn this ending.