I would expect DVD Architect Pro and Studio are pretty much done products at this point. They're both stable, and they both do pretty much everything they need to do.
Particularly since the professional world is phasing out of the DVD and BluRay business.
I don't agree that Blu-ray is on the way out. 4k blu-ray will be available soon. DVDA crashes if one tries to add subtitles in a 3D project. Save markers crashes aswell. Sony support is the worst I have ever known. They take months to reply and then the reply is rubish.
I find DVD Architect 5 (both Studio and Pro) pretty much flawless with my workflow. And I find their phone support, as well as the support on these forums, terrific.
Fortunately, there is no shortage of alternatives out there.
The problem I have is producing 3D blu-rays with menus. The only reasonable priced products are DVDA Pro and PowerDirector. PowerDirector only produces AVCHD 3D discs. There is a free MVC encoder called Frimencoder and tsmuxer can produce a 3D blu-ray disc without menus.