This doesn't answer the original question, but here are two comments.
a.) Even a few, let alone many, file system resizes make the file system inefficient. This
goes for both ext and XFS. (Btrfs is in a different category because it allocates in
chunks and when a fs is resized, a drive is added or replaced, or removed, the chunks are
relocated. Resize is just a variation on a balance.) The better option, is to fix the size
of the file system at the largest it would ever practically be in its lifetime, using LVM
thin provisioning. And use fstrim occasionally, instead of resizing the file system.
b.) A non-GUI option, that establishes a fairly consistent vernacular among various
storage technologies (md raid, LVM, btrfs), is the system-storage-manager package. Its
syntax is more btrfs like, rather than the multi-step and rather esoteric commands needed
for LVM. For example:
http://www.fpaste.org/98515/
There's a pile of really useful info here. It recognizes LVM and btrfs snapshots, LVM
raid (in contrast to LVM on md raid), thin pools and volumes, btrfs subvolumes, and so
on.
Chris Murphy