How well it's actually painted and finetuned with the shader and the rest of the environment is completely irrelevant to you.
Why it would be relevant for me in tech discussion? Its not like other games doesnt do the same? Its about resolution in the end as a tech goes, not about artistic fit.
In terms of art i think that Halo 4 is a huge step forward. Its getting much closer to what CG and TV ads were in terms of dark, greety SF, instead of colorful and cartoony game with lasers and power ranger suits. Reach was already a step up, but Halo 4 is much better in that regard.