I don't know how controversial this will be - but I'm wondering whether packages which break semantic versioning should be re-versioned by distributions to 0.X.Y versions (perhaps with a X.Y.? -> 0.X.Y transformation), until they prove themselves willing to maintain API stability enough for an official, community-accepted, non-zero major version.
Specifically for Haskell packages, they are not expected to change their interface on the 0. versions.
What is perfectly reasonable, by the ways, because it makes the schema basically useless. If people did it, very soon all the packages would be free-form 0.X versions, if not by their fault, it would be because of a dependency.
It makes much more sense to forcefully increase the version, instead of decreasing it.
(Also, notice your sibling that explains that mtl strictly followed the numbering convention.)
