Although the above formulation already corresponds to a functioning additive QM/MM scheme, including polarizable embedding by virtue of the self-consistent charges, the application range is fairly limited. First of all, it is not a true crystal what is being computed. One is simulating a defect in an otherwise ordered crystal. The surrounding molecules are ordered correctly and respect the symmetry, but the unit cell will have a different internal geometry and arrangement from all the others. Given this fact, the cell parameters cannot be optimized and it was also not completely clear how the cohesive energy of the crystal could be computed. Moreover it leads to an inconsistent treatment of interactions. The interactions between molecules in the central cell are treated at the QM level, but interactions with neighbouring molecules of the next cell are treated at lower levels of theory. This imbalance can lead to severe distortions of the molecular geometry. Finally, one last drawback is the unfavorable scaling of the computational cost. The QM region spans the size of a unit cell, which is not necessarily a single molecule (or the size of the asymmetric unit) and can therefore become quite large even for small molecular systems. The computation of properties is severely limited and the energy nor the geometries in the crystal will converge asymptotically (in regard to the QM method applied and the quality of the embedding). Looking back at the wish list proposed, there are several points which need to be addressed. The extensions we propose in this work not only overcome most of the aforementioned limitations, but also provide a more quantitative analysis of molecular crystals on an inexpensive and convenient basis.