A comprehensive analysis of shear flow-induced microstructure phenomena exhibited by discotic mesophases is presented using a complete generalized non-linear theory that takes into account short-range order elasticity, long-range elasticity, and viscous flow effects. The following four distinct shear-induced stable planar non-homogeneous microstructure modes are found: (1) long-range elasticity-induced steady state, (2) bulk tumbling-boundary wagging state, (3) bulk wagging state, and (4) viscous flow induced steady state. The stability of the microstructure modes is presented in terms of a rheological phase plane spanned by the Ericksen number Er (ratio of viscous flow to long-range elasticity), and the ratio of short-range to long-range elasticity (R). The steady and dynamical features of the various microstructure regimes are thoroughly characterized and analyzed. Two strong surface anchoring conditions, along the velocity gradient direction, and along the flow direction, are employed to investigate their effect on the stability and range of various microstructure regimes on the Er-R phase plane. The average bulk orientation for all the modes is found to be close to the velocity gradient direction. The fixed anchoring along the velocity gradient direction transmits the anchoring conditions into the bulk more strongly than that by the fixed anchoring along the flow direction. The effects of long-range elasticity on the flow-induced microstructure features are characterized. These simulations provide useful information to process carbonaceous mesophases by identifying the principles that govern shear flow-induced orientation in discotic mesophases.