Well, if the key weights fell off of the Kurzweils, then they fell off nearly everyone's keyboards since Fatar is the most popular keybed produced....
You mentioned the PC361 and the PC3 (which I own). The entire PC3 series was discontinued a few years ago. The PC3 series was replaced by the PC3K series; Kurz then came out with the LE line. Once the PC3 series was discontinued and the PC3K series took its place in the market, distributors marked the PC3 series down in order to blow out the remaining inventory and make room for the more expensive PC3K series. Suggested retail on the PC3 was $2830, however I paid less than half of that for mine once it was considered discontinued. Same thing for the PC361, they were also blown out. The PC3K7 is 'generally' $2995 on Ebay, still way less than the Stage 2. IMHO the Kurzweil will run circles around the Nord. The Nord has a better piano and B3, but in virtually every other category the Kurz sound better. The orchestral sounds of the PC3 are considered world class and the Kurz is hands down the best MIDI controller.