You know the problem relates with the meaning of words, like modern opposed to old when that meaning does not exist regarding art: Modern art does not mean that it is more "modern" than other forms of art namely for instance hiper realism that is pretty much opposed to modern art.
Regarding architecture "modern" is also related with an abstract form of expression, by opposed to some other forms of expression, for instance Pos-modernism, that in fact is not modern since it uses traditional references. Both are contemporary styles.
Regarding NA and since sailboats are imminently functional objects an approach towards functionalism is fundamental. That approach is carried to the limits in what regards "modern" boats while on other contemporary boats, on those that use as reference traditional and classical forms, the functionalist approach is used in what regards the essential "working" parts of a boat but they don't go to the limit in what regards less important (in what regards performance) parts, like cabin design, bow and transom design were traditional shapes can make the difference in what regards the perception of beauty without a significant loss in performance (in what regards cruising).
The key word is the perception of beauty that for a "modern" NA is directed linked to a fundamentalist approach regarding performance (fast is beautiful) while for a "traditional" Na beauty does not exist out of shapes and forms related with tradition.
Pascal Conq, from Finot-Conq made an essay where he developed that concept of beauty ("modern") related with absolute performance. According to this way of viewing things race boats will represent beauty in itself and cruising boats to be beautiful have to follow race boats lines, at least in what is possible, since they have other requirements in what concerns interior height and interior light.
take for instance the design of the new Dehler 46: it is a performance cruiser but it looks like a very sharp racer and therefore is beautiful according to a "modern" perspective of beauty. Of course I am quite sure that the "beauty" of its lines will have no interference in the cruising quality of the interior space that will be luminous and luxurious: