In terms or practicality of design (with regards to plates) the top outfit is roughly on par with the following design:
The main difference is the top model has a few more decorations and a gambeson (which will, in itself, provide a hefty bit of protection).
It’s not that you can’t have a split breastplate (the Roman army did) but that only makes sense of you have shield or other means to protect the gap. With a two handed weapon – you need to be able to trust your armor to protect against all kinds of weapons.
A “cuirass” made of boobcups and decorative plates is really only going to protect you against much but attacks that chainmail or a gambeson wouldn’t already protect you against.
Yet there still are plenty of companies, marketing teams, artists and fans who claim it’s too hard or inherently wrong to make two people with the exact same role wear the exact same gear, just because one is a man and one is a woman…
