Maybe it would be possible to shoot at 60fps or even higher and then dynamically adjust the frame rate to keep the 24fps but smooth some scenes as required?
Film or video shot at high framerates will necessarily have to be shot at higher shutter speeds than films shot at a lower fps. This has an obvious visual impact on the image.
As you need to add VFX, basically all content is shot with as fast a shutter as possible, and you add the motion blur back in post. And, as you rightly mentioned, when you do that you can choose any shutter speed in post.
Dealing with motion blur when rotoscoping is a bitch, btw.
Making it look good is akin to polishing a turd.
We saw the second one in 24fps 2d (we mostly avoid 3D because we rarely care enough about it to pay extra, but it was the only way to see the first one in 48fps) because we both hated the first one's presentation so much, so I don't know whether we'd have experienced it in that one.
I've never had the same impression from TV or home movies which is 50/60 fps.
I for one, don't like that kind of high frame rate motion -- it looks as fake as bad CGI graphics.
I saw all the Hobbit movies in 24fps, and—especially (at least, this is where it first really stuck firmly I in my mind as wrong) in the underground scenes in the first, but also in parts of the other two—had a similar impression.
I think it had to do with some other element of cinematography particular to that film series, though it's quite plausible that 48fps exacerbated it.