On the missile design screen, the tech level of armor available does nothing to help with the ablative armor. Could you make higher tech armor use less space to get the same protection? At max tech maybe have a 1/4 msp be enough for 1 point of ablative damage. This would keep it from getting to powerfull quickly, but would allow higher tech missiles a better chance to use the ablative armor. Right now, the only time it is worthwhile is on very large missiles where the percentage of msp used is managable. On a size six missile it is a major part of the missile, where as a size 24 missile it is quite easy to fit on.
Brian