Texture Rendering Question

I've noticed quite often lately that textures look different depending on what they're applied to. Avatars have a different lighting system than prims, which have a different system than the ground. I was wondering why the clarity and shading was different on each form. Why not use the same rendering engine on all three?

I was also wondering why it isn't possible to apply an alpha map to avatar skins. If it's a security issue regarding invisible people spying on others, that sort of thing is already possible with invisiprims and/or "burrowing" animation overrides that keep you stuck in the ground, or with a simple invisible camera follower that conveys all that it hears to you. The community at large would like a way to make their avatars translucent, digitigrade furries everywhere want to invisi-map their legs so they can use prim legs and not cut out pieces of the landscape behind them when others look at them, and people who wear shoes want to invisimap their feet so they can wear shoes without them showing through.

I'm going to forward your question on to Linden experts in the know. That being said, I've thought for awhile that making an avatar fullbright would be great for cellshade effects.