There are a lot of things that bother me and could be improved:

Lacking Hardware support for Fingerprint readers: in my Lenovo Yoga 370 i could not (for gods sake) get the Fingerprint reader to work. But I gave up trying a couple years ago. So it might be working now but i don't know. I know its not the OS fault because it is just missing key Materials and driver support from the manufacturer. But in the end I don't care whose fault it is. It does not work, and that bothers me.

Not easy to use TPM for LUKS: why doesn't the installer of any distribution use the TPM module for storing the decryption key for LUKS. Or at least make it an option. They are made for that! TPM is not your enemy. Use them to help you! Better to use TPM (with exported strong recovery key) instead of having no encryption at all or a weak password.

Proper Backup and rollback Baker info the distro: why was only Opensuse able to have an integrated solution for backup and rollback of OS changes and updates? MacOS has this since years (maybe decades...)

No parental control features: Plesse give me things like settings usage time limits and APP access limitation for specific user accounts. I know I can somehow do this via Polkit. But this is not user friendly and too complicated for typical use cases. I am very happy that GNOME is currently working in a solution for this in GNOME 50 (Propably)