Seriously though, I don't know what anyone else was expecting from this given that this has been the trend Bethesda's followed since Oblivion.
Personally, I expected something along the lines of what
Skyrim felt like compared to
Oblivion. Make no mistake,
Skyrim had plenty of flaws, and I certainly don't think as highly of it now as I did when I first played it, but it wasn't afraid to distinguish itself from its predecessor, and in fact made a ton of improvements. The dialogue was much more naturalistic, and even let you display a rudimentary personality in your choice of responses. The environment was bold and striking. The history and lore behind the setting, and how the current story fits into it, were unique and distinctive in a genre that usually seems to aspire to homogeneity (don't even start, Rushy). There were plenty of memorable towns, there was a fascinating culture to the population, etc. And they even got some fantastic actors like Christopher Plummer and Max von Sydow to lend some gravitas to the proceedings. Again, there were flaws, the two that stuck out the most for me being the poor quest design and removal of the attributes, but it was still a bold step for the series, and Bethesda clearly put a huge amount of time and effort into it.
By contrast, F4 is mostly just more of the same from F3. The setting is basically the same - it's neat to see some of the landmarks of Boston, sure, but they're few and far between, and when you get down to it, it's pretty hard to tell one major city from another when you're just picking through the rubble. The buildings you can explore are the standard factories, hospitals, offices, etc. that we've all seen before. The enemies are usually the standard Super Mutants/generic raiders/
zombies feral ghouls. The main quest is once again a sappy, cringey melodrama with a prescriptive role for the protagonist to fit into, and as I noted earlier, it's basically a role-reversal of F3's story. I could probably go on, but the point is that they didn't have to do any of this. Like Crudblud said a few pages back, the Fallout setting is fanciful enough to let you get away with including pretty much anything you want. Set it in Alaska and have Russia invade. Set it on an island a post-war nation is trying to colonize where the protagonist stumbles onto Things Man Was Not Meant To Know in its ancient ruins. Set it on a pre-war moon base where the current inhabitants are trying to decide whether or not they should try to return to Earth. It's not hard to come up with ideas that don't rely on elements we've already seen.
A design document from Bethesda for F4 has been leaked:

Also, there's this, which is very real and in no way a joke: