The notion that Joel is treated contemptuously by the game's developers just seems silly to me. You act like he was just shot two minutes into the game and then forgotten or something. His presence in Ellie's internal life is felt throughout the entire game and indeed determines its outcome. Joel is routinely humanized throughout in the form of memories that Ellie relives long after his passing, all the way through the game. Ellie's entire character arc is shaped by Joel's passing. In many ways, both Ellie and Abby exist in relationship to Joel and as representatives of different aspects of his personality.
I've definitely felt the weight of losing Joel throughout my playthroughs, although maybe I'm predisposed to being that I've lost my whole immediate family too and my dad was well let's just say no Joel. That's among the many sense in which I mentally-emotionally connect to Ellie's position a lot. It really, really hurt to lose Joel. Even after it's clear why he was killed, it still hurt a lot. I mean the way that scene concluded when Ellie entered the room...the scene at the grave site, visiting Joel's house, the compassion that Dina in particular shows to Ellie...Tommy's impulsive response, admittedly...maybe I'm an overly-emotional sap (I'll admit that I am cryer; I tear up easily), but that shit got to me. It really did. It has me bawling like a baby every time. I was emotionally aligned with Ellie's decision to pursue Abby and the others even though I really knew it was wrong. The humanization of Abby did provide a welcome new perspective on events to me and went a long ways toward bringing home the game's core points about not just revenge in a literal sense, but like finding yourself psychologically trapped, prevented from moving forward with your life, possessed in a sense by loved ones or other treasured things that you've lost.
Anyway, I didn't feel that Abby's characterization was wholly at the expense of Joel's. I mean she pretty much winds up in a Joel-like role herself vis-a-vis Lev in the end, ironically enough. Still, I always felt the most like Ellie throughout even if she's not really my favorite character because I see myself as a very flawed person prone to making the wrong decisions often and I just generally have probably more in common with Ellie than I do with any other video game character really in terms of lived experiences, including real struggles with just not liking myself or feeling like I have value so much as just being a burden to the world. Abby's morality shifts a little too much for me to connect to quite as much and the people who like her the best often seem like just generally judgmental people. Sometimes I feel like saying "You don't actually have to only care about Joel on the one hand or Abby on the Abby on the other, you know? There is this other, main character in the game too who nobody seems to remember or care much about." But then I think that I'm being selfish in a way by thinking that, just because I feel like Ellie a lot when I play this game. Well anyway, I've gone on too long and gotten off-topic a bit with musings that weren't called for. Sorry.