Well the final threads hit on what I was going to suggest. If you have to have the perfect proportion model, Make it. You said you make models to perfection. I'm sure from this thead you have your followers that will buy your product. DAZ and Efrontier, like everything else follows the money, They are not going to change their main mesh to make her more Ideal to the people who desire that look. They might sometime branch off and do that when the rigging can move the body parts more correctly  without distortions. but what's the use going that direction when their customers demand the Idealistic at this time and point. 

Until then, If you have to have everything  to your perfect porportions, your just going to have to do it yourself. There are programs out there that can make you happy and do it the way you like. Of course theres a much more complex learning curve and a lot more money to be spent. But hey!  go for it. If you look at the artwork that is done with the Mil figures, the largest percentage of the renders are fantasy based. They are not going away from there bread and butter. This is a buisness not a debate for them. I always say don't talk about it. Do it. 

I'm sure you have a good start with your followers. There is room for the perfect perportion girl. But number of sales is a whole new reality.  But if you make her the way she should be you will have her to work with for However you want to render her. And as a bonus, you can then sell her.