Would it be faster to perform a new install?
What would be faster if if you would've taken a snapshot of your root filesystem and descendants as, for example,
zfs snapshot -r freebsd@11.1-RELEASE
at which point you could simply rollback to that snapshot within maybe three seconds, reboot for good measure, and you'd be on a fresh installation.
It wouldn't be faster, but there's some stuff that gets installed in
/boot (like fuse), in /etc, and other places on the filesystem besides in
/usr/local, though if you did
pkg remove -a
, that would remove all the software you installed except maybe a few files here and there, configuration, mostly, and some empty directories or directories with files the installation script doesn't know what it is...
As for going back to the original, if you don't have a ZFS snapshot, I'm afraid you should boot from DVD, and use the configuration wizard to install 11.1-REL on a ZFS filesystem, and configure it for it to boot from that for you, then take your snapshot when you first reboot and update.
I hope I'm making sense, I'm very tired...