Would it be possible to have onboard systems measure it, and then relay it to ATC?
ABSOLUTELY! Use the human side of the human-machine interface!
Most experienced pilots can tell when the antiskid cycles the brakes, and can detect the minor swerving when one side of the runway is slipperier than the other. Tell Tower or Ground where you experienced the most active antiskid cycling, so they can take care of it AND advise others.