I suppose it is possible you got one with 7 bad encoders but chances are updating the firmware will fix it. The contacts in the new encoders loosened up over time more than the old encoders and the debounce code could not keep up. Two things you can always rely on Waldorf for, topnotch hardware and buggy software, but they fix the bugs for the most part and the ones they don't fix probably are not actually bugs but limitations in the technology/design compromises; like aliasing in the Blofeld, they could "fix" it but leaving it gives it a lot more versatility within its intended range and is why it sounds so good in that range. The only real issue for me with the Blofeld is the noise gen, it is fairly limited in use because of the aliasing.

I get why you dislike the knobs, but they don't bother me. Many dislike them and I have seen various fixes like shrink tubing, tape and rubber bands as well as just replacing them. I just learned to pinch the knob a little tighter. Skipping their traditional coating on the knobs was probably one of the corners they cut to get the price down while keeping the same quality overall.