Eszett variation sequence

[Christoph Päper]

U+00DF Latin Letter Sharp S ⟨ß⟩ has at least two rather different visual styles
resulting from a ligature of either long and round lowercase S, ⟨ſs⟩, or of long
S and normal or tailed lowercase Z, ⟨ſz⟩ or ⟨ſʒ⟩. Most modern typeface designs
follow the first style and sometimes the right-hand side is quite distinct from
the shape of the round S in the same font. In some cases it makes sense to
distinguish the glyphic origins, because, by orthographic or graphotactic means,
for instance, an _sz_ digraph is appropriate in different places than an _ss_
repeated letter.

Would it make sense to propose standardized variation sequences for these styles
or should this be left to font features like `cv##` or `calt` in Opentype?