Either you accept the walls or you go with PureScript (which could be described as "Elm without the walls"; but then there is a lot more to learn and a whole plethora of frameworks where Elm has the one-to-rule-m-all-FW baked in).
Also, Evan has not closed this issue since 2015. Most probably it is about "too much work to get it right" rather than "I'm not convinced that we need it".
With comparability you can use the operators (<,>,<=,>=,==,/=,etc.) on various types. This is not how Elm usually works. I.e. the `map` function is different for `List.map`, `Dict.map`, `Maybe.map`, etc.
In Haskell and PS you have type classes. Some types can be mapped, some can be compared, etc. Then the type class defines what functions should be implemented for such type in order to be part of the type class.
You think it's a small change, but it is pretty much what sets Elm and PS apart. Errors can also get a lot more complex with code that leans heavily on type classes.