Yeah, well,
I think it's key to distinguish a remaster from a re-mix. These days it's possible to slice and dice a recording so surgically that the lines can get blurry. But as a rule, remastering will not include any extra source material in the mix. Of course, once any other audio is added and mixed, the resulting recording will then require it's own master but that's not my point.
It's a process that not only polishes the sound but makes the recording able to be produced in the format of choice along with adding data that playback devices will employ. Usually pretty subtle stuff. Most remasters are the result of someone feeling the original can benefit from a new set of ears and gear. Unfortunately many overdo it in hopes of making the new product stand out from the original..often leading to disappointing results.
Buttons are not toys.