I fully agree. Hopefully libguestfs support will be added to GParted soon; as changing the partition layout and resizing the file systems within these partitions is usually a hand-in-hand process, it should be controllable from a single tool.
Unfortunately, as I understand it, the tools accompanying libguestfs aren't capable of resizing a file system in-place -- a major downside compared to what libparted could do, as you don't necessarily have a spare hard disk in your servers.
This is true, but really gparted doesn't need to use libparted (or libguestfs) at all for resizing. It should just call out to the native tools like resize2fs or ntfsresize. That's all that libguestfs is doing underneath the covers.
While obviously gparted folk have got a bit of development work to do, which you can argue was made necessary by changes in libparted, really they should have taken a close look at all that crufty filesystem code in libparted, run a mile, and used the native tools a long time ago.
