Eh, Fallout 4 is good but New Vegas is still the king. Fallout 4 had a lot of potential but it didn't live up to a lot of it, for most people anyway. I'm one of those rare few who DIDN'T get overly hyped about it and was able to enjoy it without feeling disappointed because it wasn't New Vegas 2.0.
That said, it did have a few minor issues. Well, I say minor. They're minor for me cos I was still able to enjoy the game even though they were there, but yeah. One issue was the fact the protagonist was voiced. That cut REALLY hard into the RP-ability of the game. Also the forced backstory. I loved that you could start pre-war and get to see the bombs fall before going to post-apocalyptia, but the forced backstory was a bit much.
Oh, and my second problem with the voiced protagonist was the fact it made it so that mod authors who made quest mods had to either record new dialogue for the protagonist using new actors who sound nothing like the originals, or splice audio from within the game files. Neither of which are particularly good options.