Indeed. I have no problem with gory games (heck, like I mentioned earlier, I love titles like Killing Floor 2 and Soldier Of Fortune 2). But when you are making what is supposed to be a super-serious narrative-driven game, you need to have some sort of reason for it beyond just "heh, look how mature we are".
On a different note, do you know how sad it is that I think that this game's ending would've been better if it took a few nods from the latest Rambo film (which itself is flawed, but not to this game's degree)? Like, picture this scenario.
Instead of bringing in an entirely new faction at the last minute, have Abby and Lev indeed meet up with the Fireflies and set up their base where the final act is. Ellie goes in to avenge Joel and the like, and her also having to take down Fireflies I think would add an extra layer to this, as she's also in a sense getting back at the organization that caused all this to begin with. Then when she does confront Abby (taking a nod from Last Blood), have her indeed manage to kill the latter, maybe even in the same way as that film (rip out her heart, symbolizing what she did to Ellie). Then she looks at Lev, realizes how far she's gone, and toss him the knife, gesturing to him as to imply that she letting him kill her for revenge. Only for Lev to toss the knife away, stating that he won't go down the path that resulted in Abby's death. It then ends with Lev leaving on the boat, and Ellie returning home to find Dina gone, but that she left a final message for her.
I know, this is really amateur, and probably not even as good as what actually happened. Just a thought.