When Adobe makes modifications to its fonts, generally the modifications are to (1) fix any design problem (i.e., the shapes of the glyphs), (2) metrics, (3) OpenType table entries used by InDesign and other programs that can take advantage of OpenType features, and/or (4) to augment the complement of glyphs adding additional glyphs to support additional languages, currency symbols, etc.
I am aware of any changes to the Minion Pro family that eliminated any glyphs, ornaments or otherwise. Examining the OpenType font in FontLab, you can see the current ornament glyphs annotated in light red.
What particular glyph from an earlier version of Minion Pro do you believe is missing from the current version?
Apparently, a correction was made to move the glyphs into their proper Unicode positions instead of private use area.
Do you know of any glyphs that got lost moving to the new version?