  There has recently been a dramatic renewal of interest in the subjects of
hadron spectroscopy and charm physics. This renaissance has been driven in part
by the discovery of a plethora of charmonium-like $XYZ$ states at BESIII and
$B$ factories, and the observation of an intriguing proton-antiproton threshold
enhancement and the possibly related $X(1835)$ meson state at BESIII, as well
as the threshold measurements of charm mesons and charm baryons.
  We present a detailed survey of the important topics in tau-charm physics and
hadron physics that can be further explored at BESIII over the remaining
lifetime of BEPCII operation. This survey will help in the optimization of the
data-taking plan over the coming years, and provides physics motivation for the
possible upgrade of BEPCII to higher luminosity.
