I just noticed something concerning transports who are smugglers or pirates.
For them the problem they may have with this rules is not really the fact that now it's cap ships that can stop them. A single bomber can blow up a transport rather easy... not much difference by which one you get stopped. The problem is the fact that now there are more ships in general (before it was fighters + bombers, now its fighters+bombers+caps) that can stop them, since there are and were a lot lawful caps (a lot of which are owned by noobs) flying around.
So I think higher radar range detectability for caps would do more for ballance than a pirate cap nerf alone would. I still think a slight pirate cap nerf would serve RP and to an extent ballance issues.