Why don't you do that then? I'd like to hear your opinion too. 
I do think the game will be a success financially, I'll start off with that. Bethesda hasn't made a game that didn't sell millions since Daggerfall, probably.
That being said, the original creators of the Fallout series, Black Isle, had a real flavor and unique style to the game (outside of the isometric camera and turn-based mechanics). That, for me, didn't get carried through in FO3. That being said, I played and enjoyed FO3, it just took me completely separating it from Fallout except a semi-butchered lore for me to enjoy it. But the main story was not that great, the reactivity was nearly zilch and the endings, which I always LOVED with Fallout games, were hackneyed, one-dimensional and flat.
That being said, I LOVED New Vegas and thought it hit all the right notes, both gameplay-wise and flavor wise, while also being something new. On top of that, I really felt FO3 was simply Oblivion with guns, by and large. If Fallout 4 is Skyrim with guns, that is already a higher bar to aspire to, even if it takes nothing from FO:NV.
So, in a nutshell, I expect some bugginess, some flimsy main plot, some limited PC development/RP opportunities and possibly some very bad ideas, such as the voiced protagonist or more action-based combat (like removing the VATS system). There always seems to be a few bone-headed design choices with a Bethesda game that are generally regarded as just plain dumb. But I'm also looking forward to some well-designed areas, some interesting quests and, similar to TES, an increase in the role of faction quests that have excellent stories.
I'll likely buy it when it comes out, after checking some reviews and possibly waiting for a price dip. But I am still excited to play it, especially if the game leans more towards the Obsidian design concepts from NV.