On Dialog, I would not put too much stock in reviews if they're vague, and pay attention to what is said specifically about it if they aren't. Reason being, many complain about side quests, and especially, repeat side quests. Most side quests, unlike deeper story quests, tend to have the same simple generic dialog. And don't forget that story and dialog content is probably THE most personal preference of any features.
My personal preferences in RPGs regarding story, dialog, and leveling, is first and foremost, minimal grinding, while maintaining enough story elements and significant characters that you stay immersed, without feeling like you're laboring through leveling and conversations. Plus a game like this has to have good atmosphere, and it's definitely got that nailed.
FO4 is THE first FO game that really accomplishes flowing, immersive gameplay, yet it's still got plenty of content to it from attributes to story, to characters. The only time it gets a bit annoying is some of the bugs (of which they're busy fixing), and certain repeat tasks if you hang around Preston too much.
This and their The Evil Within were both sleeper titles for me that I almost passed on, and have ended up spending countless hours playing. They definitely don't get some of the little things right, but the most important things, the ones that keep you immersed, they do.