I have a triple boot:
- Ubuntu 19.10 on ext4
- Ubuntu Mate 19.10 on zfs
- Xubuntu 19.10 on zfs
All names for those 3 system in the boot menus are the same, which is confusing. Only the ext4 system is recognizable because the system adds "on sda1". Didier Roche did explain in the "Ubuntu Community Hub] [Desktop] Enhancing our ZFS support on Ubuntu 19.10 - an introduction", that you considered to add a version number. Then my boot menu would contain 3 times "Ubuntu 19.10". If you add the Ubuntu flavor it would be more useful, one entry would look like "Xubuntu 19.10".
However on e.g. my desktop I will have two times Ubuntu 19.10, once with Virtualbox and once with QEMU/KVM, so even flavor and version would still be insufficient. Other people might want to reserve a OS exclusively for Banking in addition to an OS for Office Work.
So I propose to add instead of distro nams and version; the hostname or the dataset name to the grub menu entry to give the user a way to create recognizable names in that menu. Dataset name would be ZFS specific, while hostname will be useful for ext4, btrfs and others too.
An additional remark.
ZFS will change the ways we deal with multi-boot situation, since it will be relatively simple to add or delete a Linux OS. You do not have to reorganize all your partitions.
Currently I use VMs to test/try new versions of the Ubuntu flavors, however for 20.04 I consider to use real hardware to try out those development editions. ZFS would make that relatively simple, just add a few datasets. If the Beta is finished you can delete those again :)