It all starts with the proper mesh topology.

Rigging can be changed, shapes can be changed, but a given topology is impossible to change without breaking everything.

And so far the best mesh topology in the Poserverse is the 3rd Gen DAZ topology.

Not saying it's perfect, far from it, but there's none all around better and more flexible.

I can model, but I don't have the energy left to build a complete human mesh from scratch. But if I were to, I'd copy the 3rd Gen DAZ mesh as closely as legally possible. Change and improve things here and there of course, but closely follow it's layout.

Another option would be to outright try to licence it for re-distribution. After all, Posette and Dork were made by Zygote/DAZ, too, so maybe DAZ wouldn't mind making some extra money with good ol' V3.

I think a resculpted 3rd gen DAZ mesh equipped with the latest Poser rigging tech would be the best option we currently have to have a fully Poser-compatible mesh that has the widest appeal to the masses.

Or a mesh that is very, very close to it in design philosophy, but this means you have to start from scratch again with everything, and I simply can't see that happen.

At least not if attempted by a single person without huge financial backing.