Vilters, what you are describing is a character.  It would be a bad thing if a default figure came with a base mesh with the breasts that you describe, indeed, bad if it comes as a character at all.   However, since most see a figure as presented by its CR2, it would be nice for a base figure to come with  morphs that do what you wish and have that morph preset to 1.0 by default.

At least for me, it is easier to morph larger than smaller.  I would prefer a base mesh that is flat chested with enough polys there to support relatively large shapes.  And as Zev0 sorta says,  the way the mesh is laid out should follow major muscle groups, boney protrusions, tendons etc.  Morphers shoud not have to guess where they are.

The base mesh should be developed with morphing in mind.  The figure as presented should be morphed into an attractive character.  The problem with the presentation morph being added to other character morphs can be solved by a separate Off pose and or the pose files producing another character can turn the presentation character off.