If you already own Anthology XI and the individual plugins not contained in that bundle, then you are correct in assuming upgrading will just get you one consolidated bundle license. You’ll also get maintenance and feature updates for all plugins in Anthology XII.
If you do not own Anthology XI but all individual plugin licenses, then Anthology XII will get you EQ45, EQ65, and EChannel, which are not currently available outside of the Anthology XII bundle (and previous Anthology bundles).
Physion Mk II (released Fall 2022) was the “added value” previously mentioned in this thread. Of course, we’re always working on new plug-ins, but we can’t comment on any future additions to AXII at this time.