On the other hand, weapons of old were used as part of actual wars. Precise weaponry seems to be making it too easy to kill off people without starting a war - like the US is doing with its drone strikes - which means it'll happen more. Also, I fear that the limit of precision strike weapons is being able to swiftly kill an arbitrary target anywhere, for cheap - which opens the way for ethnic cleansing, killing off political opponents, people harboring thoughts inconvenient to powerful people, etc.
Ultimately, I think precision weapons are better than blunt ones, but their development needs to happen in lock step with development of protection technologies - mostly social technologies, that would ensure those weapons can't be arbitrarily used by random politicians or countries without consequence. Unfortunately, it seems that in the last decades we've been losing social technologies - like the rule of law and trust in it.