I know there are neutral factions, but I said they needed more, at least some you could join. I also don't think you can judge the game to FO 3, as FO 3 existed before the whole "radiant quest" thing that BGS came up with for Skyrim, so the comparison is better vs Skyrim, just for quest content. I think the main problem here isn't quantity, it is quality, as too many of the quests are wayyyy too similar and repetitious.
Well, on the MQ, one of them is just go to Diamond City, another is just go to Nick Valentine office, and then a go to location and kill enemies quest. Then you have a talk to x. Sooo yeah. In Diamond City, 2 of the quests are fetch quests.
Too much repetition, and the faction quests are similar with a faction dependent variable, but otherwise they generally involve killing raiders, ghouls, or super mutants, with a faction "twist", and most quests do not have alternative methods of completion. In NV for example there are generally always a non-violent or sneaky way, or intelligent way to complete a quest, and in FO 4 it is mostly just kill, kill, kill, and done, with very few exceptions, and when there is an exception, it is Charisma.