The traditional advantage of ketches and yawls was the 'smaller' sails individually for the same area, and the additional options for balancing the sailplans.
The sail size issues were much more important in the days of 100 lb sails, and no effective roller furling, esp as the boats got bigger. Today's technology has pretty much eliminated those concerns for most, unless you're in the 'block and tackle and no winches' set.
The balancing issues are still valid, but modern designs, balanced rudders etc have probably made those less important too. And despite the alleged advantage it was not unusual to see ketches beating to weather with the mizzen furled.. but still you had the options of going to 'jib and jigger' when conditions warranted.
I think still today the 'look' mentioned above may be the biggest incentive to head in that direction. Those that want that salty, old school traditional look (which has undoubted appeal) will lean that way. For me the ideal would be 'that look' coupled with a thoroughly modern underbody for the best of both worlds and the value of the shocked skippers as you scoot by them with that 'apparent slug'!
Bob Perry's latest falls into that category, as did/do the Spirit Yachts and some others...