The future of stellar model atmospheres: macroscopic nightmares?

Abstract
Stellar atmospheres represent unique windows for understanding stellar, galactic and cosmic evolution by being responsible for the emission of stellar spectra. Much progress has been made over the years in modelling stellar atmospheres but still the modelling efforts are hampered by various, often questionable, assumptions and approximations. This review describes promising avenues for improving the realism of stellar model atmospheres for hot (spectral types O, B, A), cool (F, G, K) and very cool (M and later) stars, respectively, in the coming decade. A common theme will be time-dependent 3D hydrodynamical calculations with a detailed non-LTE treatment of the radiative transfer. It is argued that this is fully within the realm of possibility on this time-scale and indeed will be necessary to complement the expected advances on the observational side.