In this paper, we consider the modified model of semiconductor lasers (SCLs) subjected to optical feedback and we showcase the main dynamical features that emerge in this system by emphasizing the prominent role played by the new control parameter namely the mean of effective gain coefficient (MEGC). A detailed linear stability analysis is performed wherein many approaches allow to put forth accurate limits of steady state, relaxation oscillation and chaotic areas controlled by MEGC. The process of the modulational instability is stuck out and the diagonal break-up of the ellipsoid enclosing external modes and antimodes is carried out leading to coherence collapse phenomenon and the excited mode scattering that is gradually extended by increased MEGC states. The route to the narrow linewidth at the limit conditions is fulfilled under the drastic impact of MEGC likewise the dependency of Hopf bifurcation parameters, as well as mode excitation and induced destructive interference of optical feedback in the modified potential well model.