IMO that kind of sxyboxes is damn cool, but...the textures might need upgrades. They should look better, seriously...and there are texturers able to do that. 
It's not a matter of making the textures look better, it's that if you want a skysphere that is actually high resolution one, you need to use a pretty wide field of view to avoid blurring...
Example: Your screen has width of 1024 in pixels (yeah, I know it's a low resolution but bear with me). If your field of view is 90 degrees, your screen will fit 1/4th of the sphere circumference on it horizontally. That means that to avoid blurring, the texture resolution should be at least 4096 pixels for equator, meaning basically a 4096x2048 resolution texture.
If your field of view is 45 degrees, you will need a 8192x4096 resolution texture to avoid blurring.
To use a texture with 8192 dimension you need a relatively new GPU.
...and this is just using a 1024 pixels wide resolution. And not counting spherical distortions of high fields of view...
