Judging from whats been revealed so far, I'm expecting the Boston wasteland to be a much more optimistic place. The capital wasteland, for the most part, was desolate and hopeless and depressing.
My first instinct tell me, that while playing Fallout 4 the overblown optimism might turn me off after a while. Suffering being such an integral part of human history and nature, I feel that the bleak wasteland was in a lot of ways immersive and gave a lot to the imagination. At the time, I was going through a dark time of my own so the capital wasteland to me felt like I was at home.
Do you remember? exploring old, rusty, abandoned vaults with their own backstories. Body parts and blood everywhere.. finding computer terminals with bite sized pieces of a story, just one piece of a puzzle. There was so much narrative in just the environments themselves, you didn't need dialogue to explain to you the horrors which have occurred. It lends a lot more to your imagination and that was really amazing to me.
I have friends who could not play Fallout 3 because they didn't have the stomach for it.. I think that is very telling how well Bethesda pulled off their vision for Fallout 3. Personally, I'm a little worried that the overall optimism won't relate to me as much and I can't quite get into it. But I guess time will tell.