What are the prominent downsides of the D programming language?

[jmh530]

On Tuesday, 29 September 2020 at 18:38:29 UTC, mw wrote:
> [snip]
>
> Good to hear, I opened an discussion issue here:
>
> https://github.com/jll63/openmethods.d/issues/19
>
> Anyone who's interested in the implementation, let's continue 
> the brain storming there.

You might recall that back in June I wrote [1] that D does not 
have the ability to properly disable base members and member 
functions, which would make implementing Eiffel-like semantics 
significantly easier as part of the base language.

[1] 
https://forum.dlang.org/post/tpwwzkvcarqquqslspul@forum.dlang.org