Prospera is my favorite character.
A prequel centered around her, be it a short series, OVA or a movie - essentially what the Origin OVA is for Char - has become my pipe dream anime project.
One that will most likely never happen, unfortunately.
But daaaaaamn, can you imagine what a sick ass anti-hero/ villain protag character study that could be? Watching that woman become increasingly desperate and unhinged as the health of her child progressively fails, then watch her complicated-ass feelings as she raises Suletta? Watching more and more of Elnora get twisted and warped into becoming Prospera? Holy fuck that'd be lit as fuck! Plus, there's so much cool story you could insert in there if you wished. Like, at this point it is a commonly accepted fandom headcanon that Prospera and Mio's mom knew each other... there are many places you could go with that. So on and so forth.
Done well, that shit would unseat War in Pocket as my most appreciated piece of Gundam media. Alas, pipe-iest of pipe dreams.