Other than being able to play online, what are the technical improvements?
"Widescreen" is not new, the original game had this on N64.
Resolution and improved frame rate? Both done on emulators since forever. Controls were not an issue with the original either, can be easily adjusted to play the same as dual stick modern shooters. Even with proper dual analog.
The Switch emulation seems to struggle a bit from the video. XBOX version obviously looks less janky since it can handle the N64 emulation much faster.
But still.... it's just emulation and nothing else?
From that trailer it's identical to the original so i'm not sure what you are talking about.
Nope, that feature was introduced in Perfect Dark.
Which you could always turn off very easily in the options.