Hello!
Excellent project, good luck on that! My two cents on this, I think, can be summed by what Exynox said:
It is excellent either if you want to keep your own server, start a new field, an university / hobby project or the likes of QuantumCore for the OG's in the back. But for the end user, it might be an absolute pain, and I mean this also if we end up with newer sources in our hands.
I personally work on sources I have been meticulously stripping and updating since 2014. To the point that in 2022 I was already unable to provide systems working on other sources. Currently, my server is in Rust and my client is not having a single piece of their old EterX DX8 code. Which makes it really good for me and my own usage, but really bad for anyone else or even just me trying to sell or share systems that would work "as-is".
All the resources exists for the 2014 sources, which makes it already extremely hard to maintain all the existing branches, some people already do not give support for Ava or N2 sources, some systems have a Marty version, some other have an Owsap version. The end user basically will not bother trying something that changes everything from the ground up because at the very first bump in the road, it will be them and only them and their knowledge. We even, to this day, have people asking for help on 2010 tutorials that are now outdated with the .txt protos and the knowledge base of pre-2013 wasn't even fully ported to the 2014 sources for the beginners. This is for the same reasons that most "advanced" users out there still recommend Marty's or TMP4 sources (or Owsap with support), because the potential of having something go south without any resources is lower than with other (leaked or sold by less advanced users) sources.
However, this is an interesting project to take upon!