Fallout 4 is such a major improvement in most areas over Fallout 3/NV and Skyrim. I didn't think they'd be able to do it but they cut out most of the bugs that plagued the engine. It has a fraction of the glitches that Skyrim and New Vegas had. I'm 240 hours into the game and I've only had two glitches of note--one has an easy workaround and the other did not repeat when I reloaded a save. I've had four crashes to desktop, two of which were related to the bugs I mentioned. With Skyrim, I crashed once a day.
As for size, the idea that it's short made me chuckle. I'm nowhere near finishing the main quest, I haven't done the Brotherhood of Steel questline yet, or the Railroad questline. I'm still swimming in side-quests.
It's kind of funny to read people only talk about what they feel are the negatives compared to older games but why don't they mention all the improvements? Guns are so much better now, especially with the new modification systems. The addition of reflex mods ALONE make Fallout 4 more fun. Settlements are a massive improvement, as are companions. There is a companion that will fit your playstyle.
It's not a game that holds your hand and makes your choices for you, though. If you're someone who complains about freedom and wants a game to force you into picking one path or one style of play then you might want something else.
Personally, I'm absolutely loving it. I do what I want when I want. Sometimes I just want to explore, or work on securing more settlements, or building up my settlements, or working on my armor and weapons, or following one faction or another. My character is who I want them to be without being led around by the nose based on a highly flawed "karma" system.