I have the Yachtmaster already...I would probably have to sell it to get the Datejust. But the current price on the steel/platinum Yachtmaster is $8,500.
It looks like you might be going down from 35 mm to 31 mm. I'm familiar with the size 33mm and 38 mm of the j12s so quite curious of size if woman's YM Rolex.
The ladies YM is 29mm, so it's a bit smaller than you are used to. The midsize is 35mm, and the midsize DJ is 31mm. I love the size of the 35, but I had a men's DJ at 36mm and it looked too man-ish on me, so if I get another DJ it will be the midsize. The ladies versions are way too small for my liking.
I'm sorry but I really think you should keep your yachtmaster! It is TDF and I would never switch. JMO. Plus, you might take a loss and not get back what you paid for it. Have you considered that or if you love the others so much more - then I guess it doesn't matter. But get what YOU really love!