Steve,
Yes, that's one of the major advantages of 4.x - the pool is now much easier to copy or backup.
If you upgrade an existing 3.x installation then the hardlinks will still persist for the old backups (4.x is backward compatible - it knows how to view/restore 3.x backups). The 3.x backups will eventually expire, so the hardlink use will eventually go down.
In 4.1.0 there is a new utility BackupPC_migrateV3toV4 that you can optionally use to bulk upgrade old 3.x backups to v4 format. Although that might take a while, it allows you to eliminate all the old hardlinked backups.
Craig