It is not really about the discussion, it is about the developer time available. They have a huge heap of outstanding tickets they work through and their priorities are currently elsewhere.
It would be good to see the above conversation about multiple Fronts being added to the Guidelines. That would be an improvement if it was officially allowed as I know there some editors who believe in one Front only.
OK - I understand. So maybe this should be simply put on the “wishlist”?! 
In MB terms that is translated as “vote on the relevant Ticket”.
Can you point me to the ticket you were referring to? Glad to read it and eventually vote…
Sorry, I have no idea. There are so many tickets lost in that system so I don’t go in there. It would mess with my head too much.
Yeah… 2012. That’s why I can’t look at tickets. 
Yeah, there does seem to be quite minimal development on MusicBrainz these days, no major improvements for many years.
Reviving the topic 
I have this problem myself and I looked at the forums and found this topic. My main problem is using the correct cover art for CD’s that are part of a box. From the earlier discussion it seems that the problem is not resolved, but I have the following experience.
About a year ago I added (with the help of more experienced people here) the following Engelbert Humperdinck box set
I did not add cover art at the time. When I used Picard to load it into my music library, I found out that each one of the 11 discs came in Kodi with its own separate cover art. Several days ago, i added the cover art for the box and it also appears quite correctly in Kodi, and has not displaced the separate covers for the different discs.
I have tried recently and unsuccessfully to achieve this for another box set:
But much more notably, the box set Discovery of Pink Floyd
suffers from the same problem - the individual discs share the cover art of the box.
I tried to analyze the reasons, and tried various tricks when entering stuff in my database, but no access. Now, apparently having separate covers is completely achievable (Humperdinck), only it is not clear how, as this years’ old discussion shows.
Any ideas, thoughts and help would be appreciated!
You have more of a KODI issue that a Musicbrainz one. Go to the music forum there and dig out the thread about boxsets. Mainly to do with naming your separate covers correctly.
Thank you @IvanDobsky for such a prompt response! I will try and report about the outcome 
But I have to say that I do not rmember doing anything special with Humperdinck. Somehow it was done automatically by Kodi.
I think this is the bit you need…
https://forum.kodi.tv/showthread.php?tid=349695&page=18
I have not got round to it as I am still on v18…
Much of it is about the disc subtitles and numbering covers 1,2,3 etc.