Unicode subscript letters

[felileg]

While we're on the subject of modifier letters, I'd like to take this opportunity to add the following suggestion: systematize support for Unicode subscript letters. This table https://en.wikipedia.org/wiki/Unicode_subscripts_and_superscripts#Latin,_Greek,_Cyrillic,_and_IPA_tables shows that support for superscript letters is already excellent. However, only a fraction of subscripts are supported (ᵢ, ᵣ, ᵤ, ᵥ). In my case, it would be particularly useful to add the remaining vowels (ₐ, ₑ, ₒ), if not the entire set.
Would this fall within the new font guidelines?

[psb1558]

Would this fall within the new font guidelines?

I don't know. What are these subscripts generally used for? And this is a question I've always been interested in: does this request have to do with your particular needs, or is it more a feeling that a Unicode block, if filled up, might be useful to someone else?

[felileg]

I asked the question out of curiosity, because I'm not aware of the limitations of the project: technical limitations of the font, limitations in the time you have to devote to it, limitations in the vocation of the project, ...

In my particular case, the addition of vowels would be a plus for the digitization and editing of old dialectological sources. It's a rather niche field with some but little connection to medieval studies so I would understand a rejection

[Doc73]

I would support this request also for superscripts.
The super and subs are very useful for the (strange) needs of classical philologists, of whose number I, even if unworthily, am a part.
Many thanks,
DC

EDIT
I add a sample.

% !TeX TS-program = lualatex
% !TeX encoding = UTF-8
% !TeX spellcheck = it_IT
% !TeX root = Unicodefonttable.tex

\documentclass[11pt,article]{memoir}
\usepackage{fontspec,unicode-math}
\usepackage[book]{gentium-otf}
\usepackage{unicodefonttable}        
%-----------------------------------------
\newcommand{\nomefont}{%
	\directlua{
	local str = font.fonts[font.current()].fullname
	tex.sprint(-2, str)
	}
}
%-----------------------------------------
\begin{document}
\displayfonttable[range-start=2070,range-end=209F]{\nomefont}

\displayfonttable[range-start=2070,range-end=209F]{Junicode}

\displayfonttable[range-start=2070,range-end=209F]{Libertinus Serif}
\end{document}

%%% Local Variables:
%%% coding: utf-8
%%% mode: latex
%%% TeX-engine: luatex
%%% TeX-output-dir: "build-unicodefonttable"
%%% TeX-master: t
%%% End: