EXACTLY! Metal phone cases suck and I don't think Liquidmetal is the answer to the wonderful tactile feel in your hand of the contoured plastic texture of the encasing of the 3 GS. Sure the black glass and aluminum are very pretty, but. You need an outer case to help protect the screen in the case of an impact from dropping it. Metal hits hard yet plastic and rubber are lightweight and help them to absorb the impact.
LQMT should focus on hinges and such where the unique Liquidmetal properties might actually benefit in the function and usability of a personal device such as a smart phone. Doesn't need to be any lighter either. Radio signal tranperancy. Seriously? Like LQMT is the only material that has that?