Toxicity is one thing for sure but I don't like how the commercialization of MP has shaped it.
Indie games have a very different feel in their online gameplay compared to "commercial" games.
Even way back, HL1 online and those online experiences felt so different because it was designed to be about the group experience rather than level up and get a skin, buy a weapon, our skill tree is massive.
Sure technology was holding it back but I wish I could see what it would've been without the massive push for $$$.