Lets see... 1) The writing is simply awful. The plot was predictable as hell, the characters were two dimensional, and the endings were just lame. 2) There was no roleplaying. The voiced protagonist was VERY poorly done and it's telling that they removed Karma entirely. You had the option of playing a selfless boy scout or a sarcastic boy scout who liked to get paid. There really were no moral decisions until the end, and even then it was petty much which ending do you want, the Red Ending, the Green Ending, or the Blue ending. 3) The world felt fake. I've been replaying the first fallout recently and I'll tell you this, it felt believable. Fallout 4 doesn't at any point. It's not a believable post-apocalyptic world. It feels like a Disney Fun ride version of the apocalypse which kills immersion entirely. 4) The character creation system. They dumbed it down to the point you really can't fine tune your character. The current system is crap and I look forward to seeing if someone can mod it back to something approaching quality. 5) The crafting system. Ironically I find the crafting system in it's massive number of options tends to limit options. The number of guns actually feels more limited than the other games while most of the designs just are nonsensical. To say nothing of the idiotic leveled loot system that has pipe pistols showing up in prewar weapons cashes 6) The settlement system. It could have been so good but the execution sucks. Between the limited options, limited space, horrible clipping, poor perspective, and generally unintuitive nature of it, it feels more like a mod than an in game function. 7) Legendaries: We don't need random boss monsters and magical weapons. Frankly, I'm double pissed because they had an example of a 1st person fallout done right. Fallout New Vegas took the fallout 3 system and refined it. Had they taken lessons from that, and maybe hired a writer who could actually write worth a damn, it could have been great. Instead they pretty much went the exact opposing direction on everything and we end up with a game that feels like Fallout: Brotherhood of Steel 2.