Hm... I known that QT uses on Ubintu and Mint!
Note. I have many years of experience using Linux Mint. Precisely because its Mint Menu and Control Center are best, very well designed and easy usable software. (Today, Cinnamon is not as well thought-out and it's just no easy. This is not any comparison with the classical DE and controls on the Linux Mint...)
I know a lot of operating systems and DE and I have opportunity to compare and choose from the most similar OS on many existing in this world for the last few years. I know many lot of Linux distributions, various assemblies from different Linux communities. Some I use in my practice on regular basis. Including rary OS alike PuppyLinux.
Moreover, I do not judge on this subject just based on personal preferences, alike means: 'I like it' or 'I dislike it'. I speak about the ease of management of operating systems, who is have basis of estimates:
-- Whether it's in the OS intuitive based and are lightness use it?
-- Whether it be running faster for your work?
-- Are It not difficult for user and it does not irritate the user?
On the other hand, if some DE has control who is annoying user ill-conceived placement, who has uncomfortable grouping of controls and so on, what it not might be "modern" and "advanced" technology and operating systems...
To me personally the least important of all is whether the product is 'fashionable' and alleged its are 'evolution'. I just appreciate the convenience and working speed of the OS -- it's paramount. Therefore, I fully understand those people who in the present world situation ready to go even JWM! And especially in the OpenBox!
And I have been using the netbook OS with OpenBox and I very happy works with it!..
Therefore, I strongly object to the Linux Mint future oriented only to one kind of DE, supposedly the most promising and who can be 'popular' among the masses!
But the achievement possible to reconfigure the operating system on one or another DE, but certainly "one click" and without any problems, so this was a huge achievement, IMHO.
I'm not against that potentially the Mint will have the opportunity to change the DE who uses QT-based and GTK-based DEs. But only if it is achievable without any problems, some alike an inconsistencies in the programs.
If it possible, I'll be glad to see in the above panel an option:
 KDE (Note, it based on QT library and it additionally take xxx Mb on your HD...)
That's something like it...
(Sorry for the large text...)
"All is not lost that is in peril... Actions speak louder than words."
Best server side *nix; bad desktop under *nix; it's because has generic problems...