I think the entire series is what it is because of the dialogs in each game. I feel they are getting better as they go on, Fallout 4 having the best IMO but New Vegas is very close. I really enjoyed the casino games in New Vegas too, shame they were not in Fallout 4 too.
FALLOUT 4's dialogue system is one of the worst dialogue systems in any game that I have ever seen. First of all, a lot of people like to call it "Mass Effect" style. But this is plain wrong. Why? Because at least in Mass Effect there are sometimes more than 4 dialogue choices, and sometimes less. But as Trainwiz once said, there need to be FOUR, exactly FOUR, no more, no less.
Now there are many other reasons why Fallout 4's dialogue is terrible. One of the most blistering is the fact that there are many, many times where you do not know exactly what your character is going to say. And there is usually no way to "just say no!" in Fallout 4's dialogue, you are required to do something and you only can say yes or walk away. Unless you want to ask for more money, which brings me to my next point.
SKILL CHECKS make your skills useful. One of Fallout (GRUPS) 's five rules was that there should be multiple solutions to a problem. So in Fallout NV for example you can tell Jack a better way of making a rebreather if you're not the fighting type. But the only skill check that's in Fallout 4 is charisma for money (which doesn't make sense sometimes, for example some scrawny guy comes up to you and says he can kill those bandits, but he wants more money, how can you trust him that he's a good fighter just because he sounds nice?) and that STILL doesn't resolve the problem. One of the best parts of Skill Checks in New Vegas was that it would sometimes resolve the problem.
Also the worst part of Fallout 4's dialogue is the fact that the voiced protagonist is just tone-neutral dialogue which sounds the same every time and the same voice on every play-though, no matter your age, race, etc. I WOULD RATHER IMAGINE IT SOUNDING REALISTIC than LISTEN TO THE SAME UNREALISTIC THING!
And there's another issue, Fallout 4's dialogue does not have meaningful character interaction (the best example here would be how you treat your companions in Dead Money) in the dialogue. Most of the time you're just doing things for the quest or either giving a mostly positive or somewhat negative (but still "yes") answer to a question like in the main quest. I mean, there aren't a lot of moments like THIS in Fallout 4:
So anyways I don't like Fallout 4's dialogue very much. NV is first for me and the classic Fallouts were great as well (I especially love the voiced characters/talking heads; one of my other favorites is when you prank call the Enclave in Fallout 2)
