The main change is the removal of code for working with file systems, that is, now there are no mkfs and resize inside parted.
A couple of years ago, parted completely replaced fdisk with me, as it maintained the gpt partition table, which is necessary to support partitions larger than 2 TB.
Announcement on the parted mailing list:
lists.gnu.org/archive/html/info-gnu/2011-05/msg00017.html