Maybe we need to get a bit more concrete, do you have something specific in mind? The example you started the discussion with is I think a pretty clear case, https://musicbrainz.org/release/c9c23b1d-6a3c-45bd-9798-4c2311ddab72 and https://musicbrainz.org/release/1ba80c92-71d1-4d48-9060-b32d804e8f69 are really distinct.
In general I think MB’s differentiation of different releases gives a nice balance. The majority of different releases I think is fairly distinguishable, especially for new releases. Things like different formats (Vinyl, CD, digital download, …) and differences in track listing (e.g. with and without bonus tracks) are rather obvious I think.
A bit more tricky it can get with overall same release, but packaged up for different markets (such as European vs. Japanese vs. US). But often there are differences in the packaging, especially the back cover, with different barcode, catalogue number and company logos (due to different labels and/or distributor). Here it depends: For some it’s important when tagging their files, for some not. Both works, if you don’t care you can pick any of those otherwise similar releases.
Re-releases are also often not that easy, as most releases give no clear indication on the year they were released on. But usually re-releases come with different catalogue numbers and barcodes.
And then there are of course some of the really tricky ones. Things like releases with identical packages, but for some reason significantly different running times; otherwise identical track lists and barcodes but a different logo on the back cover or even more subtle packaging differences. But in my experience those aren’t the rule.
What doesn’t warrant a separate release on MB are slight production related differences, e.g. different CD matrix code or minor variations in CD TOC. Some people would like to be able to record those, but the general consensus seems to be that it does not make sense to duplicate all the other identical data just for this and that information like different matrix codes needs a separate mechanism.