In some ways yes. I think it has a good and important message about the futility of seeking revenge, though. But in terms of story beats... Yeah its one depressing situation to the next
.
One of the saddest scenes in the whole game is when Ellie finally comes home and realises she can't even play the guitar any more - the most positive thing Joel ever taught her
. Although I know there are ways to work around things like that and re-learn how to play chords with fewer fingers. I like to imagine she went back to Jackson and did that.
But yeah I do think being able to sympathise with Abby is important to getting the full effect and realising that the story isn't about getting revenge, it's about revenge ruining multiple people's lives. I think they could have done a better job of conveying Abby's regret and how killing Joel affected her. It seemed like they were hinting at her regretting it but not quite strongly enough.