I'm all for making mass driver packets visible as long as the new AI is capable of making intelligent decisions about their use. Otherwise giving the player more flexability as well as another tool for finding enemies while the AI has no idea is just going backwards.
Depending on the circumstance an AI might decide to not use mass drivers due to risk of being discovered, unless absolutely pushed to doing it, maybe for fuel or distance reasons, but once they know they're discovered maybe they can change their mind?
However, maybe enemy mass driver packets should be treated like any sensor contact, you can only see them if they're in res 1 sensor range? I know the technobabble about the aether disagrees with this, and its a huge overhead as discussed before.. Maybe like sensors it could be an option, always detected if in the same system, only detected if in sensor range, or maybe only detected with appropriate level of deep space tracking station?