There are too many unnecessary dependencies for the package man for a headless
system. The following are required to install man on a raspberry pi3 running
tumbleweed version 20160625: 
  cron cronie cups cups-client cups-filters cups-filters-cups-browsed
  cups-filters-foomatic-rip cups-filters-ghostscript cups-libs ghostscript
  ghostscript-fonts-other ghostscript-fonts-std ghostscript-x11 groff
groff-full
  gxditview libavahi-glib1 libcairo2 libdrm2 libfreebl3 libgbm1 libjasper1
  libjbig2 libjpeg8 liblcms2-2 libLLVM libnetpbm11 libopenjp2-7 libpipeline1
  libpixman-1-0 libpoppler61 libqpdf17 libsoftokn3 libtiff5 libwayland-client0
  libwayland-server0 libX11-xcb1 libXaw7 libxcb-dri2-0 libxcb-dri3-0
libxcb-glx0
  libxcb-present0 libxcb-render0 libxcb-shm0 libxcb-sync1 libxcb-xfixes0
  libXdamage1 libXfixes3 libXmu6 libXpm4 libxshmfence1 libXxf86vm1 man Mesa
  Mesa-libEGL1 Mesa-libGL1 Mesa-libglapi0 mozilla-nspr mozilla-nss
  mozilla-nss-certs netpbm parallel-printer-support poppler-data poppler-tools
  postfix psutils s2tc xbitmaps

most of those are not needed on a headless, resource limited system such as the
raspberry pi3.