I think that their older albums lacked the ability to sustain interest (at least for me). They would have a few songs that were of particular interest, but would then degenerate into typical and non-evocative bm riffing. They needed a stronger, more unified vision. You identified their thematic interests as the source of their more complete albums, and I think that that is correct. "Frontschwien" (and "World Funeral") both presented shifting sound textures and speeds that helped to break up the constant aggressive playing, and thereby were able to grab and hold the attention of the viewer to a far greater extent. They also kept the listener in a state of anticipation - constantly on edge, on the lookout for some new, as of yet unheard sound.