My base template is identical for each block; this includes contrast variation, pattern, and placement of visual elements. To say one has more depth than the other would be incorrect but most likely a result of the coloring and block shapes (model). If you were to take a screenshot, make it grey scale, and look at each of the textures you would find that aside from the brightness of some blocks, they would each contain the same visual style.
The models, unfortunately, lack design elements on the outer faces which is most likely the primary reason for the differences in their aesthetics. I tried to compensate by adding depth through the shapes. Perhaps I failed. Perhaps it would be better to stick with basic half-slab shapes and rely on textures for detail.
I understand what you're saying when you stated that they "don't seem to have a texture". This was the design style we went with; the blocks wouldn't resemble the material textures they were built with which would, A, allow the mod to fit within any resource pack without being tied to the material textures and, B, create a very consistent design style across the entire mod. It isn't uncommon to have textures that don't resemble the recipe materials. Take vanilla for example; the cauldron certainly doesn't match iron, nor does the chest match the wood texture. I tried to find a balance.
If you'd like to see the Essence photoshop template, you can download it on the
repo. You can get an idea of how my design process works from the ground up. The similarities between BC and IC2 were unintentional.