Is full-frame vignetting really an issue for landscape photography with wide angle lenses on digital cameras?
It hasn’t been a notable issue for me. In most cases, the vignetting is negligible; in some cases, the vignetting is desirable; in all cases, the vignetting is easily corrected with ~2 seconds work during the RAW conversion process. Vignetting has never caused a final landscape shot of mine to be detectably worse. In my opinion, based upon my experience, the issue is overblown.