1. Not usually a problem for most people, and flatpaks are built into the very slick and reliable GUI store to access newer versions.
2. Legitimate issue for people who need those features, though the Wayland cinnamon session is making good progress.
3. Those are fairly advanced features that most average users won't take advantage of. Cinnamon actually has pretty fantastic widgets/extensions.
4. Having a familiar windows-like interface is an advantage for first time users, making the transition far smoother. Different paradigms can be explored after they are comfortable with Linux.

For people dipping their toes into Linux, mint still has everyone beat. No other distro has such a polished onboarding experience, which already experienced Linux users tend to overlook.

1. The welcome screen perfectly walks new users getting their system set up and usable, in particular it makes the GUI driver installer front and center to avoid Nvidia users trying to install the driver from the Nvidia website.
2. The polish and stability of the updater tool and GUI store are not to be underestimated. KDE's discover is clunky and Gnome's software store is extremely slow in comparison.
3. Every common use case is covered out of the box. There will be no hunting for codecs, filesystem support, firewall, samba, etc, which can be a problem on other other distro like Debian, Fedora, or Opensuse.
4. Maintainence is simple, updates aren't super frequent (important on internet limited areas), guides written for a newbie perspective are plentiful, most commercial software not in the repos will offer a simple .deb installer package.

All of those things are critical to not burning a new user, and so far nothing has approached Mint's mastery of onboarding, IMHO.