Low res sky boxes are painfully annoying. I know with the CoD series all of the world textures have always been a bit crappy. For example, the geometry textures may look fantastic at first glance in CoD4 with all the specular and normal mapping, but when you get closer to take a look (even on ultra quality) you realize they’re just pixelated crap. It’s probably a side effect of it being a console port.
Most of the textures are 512x512 and 256x256 (often used for the BSP) - the engine allows for the usual maps (diffuse, normal, specular etc.)
CoD is a fast-paced game, you are always on the move thus highly detailed textures would be a waste of resources.
The engines limitations are very tight when it comes to materials and such.
I personally think the four or five existing skyboxes in HL2 look like shit.
Founded in 2004, Leakfree.org became one of the first online communities dedicated to Valve’s Source engine development. It is more famously known for the formation of Black Mesa: Source under the 'Leakfree Modification Team' handle in September 2004.