"I have some actual examples from a recent game, Roboblitz. In this game, we replaced about 95% of the textures. The game has 6 levels and for each level the developers would use 80MB of compressed textures. So, let's do the numbers, a total of 6x80=480MB. Using our tools we replaced the 480MB with about 3MB of procedural data, a pretty spectacular decrease in game size.”
Check it out over at Bit Tech.