Fonts are already in there and proto-glyphs are too as generalized dicritics. There's also a large variety of generic shapes, lines, arrows, circles and boxes in both filled and unfilled varieties. Lines even have different weights. The absurdity of a custom alphabet can already be partially actualized. Formalism is merely the final step

This conversation was had 20 years ago and your (and my) position lost. Might as well embrace the inevitable instead of insisting on the impossible.

Whether you agree with it or not won't actually affect unicode's outcome, only your own.

Unicode does not specify any fonts, though many fonts are defined to be consistent with the Unicode standard, nevertheless they are emphatically not part of Unicode.

How symbols including diacritics are drawn and displayed is not a concern for Unicode, different fonts can interpret 'filled circle' or the weight of a glyph as they like, just as with emoji. By convention they generally adopt common representations but not entirely. For example try using the box drawing characters from several different fonts together. Some work, many don't.