One thing to remember is that the explorer ships may also end up being a very good command ship/awacs platform. Change out the sensors that look for minerals/jump points, etc to look for ships, etc, and you go from being able to zero in on wealthy resources, to being able to zero in on threats or targets for your fleet. (see the Sensors, Radar, and scanning section of the
https://testsquadron.com/threads/exploration-guide-what-we-know-so-far.3952/ post) This gives explorer ships an additional role outside just looking for more rocks to mine, jump points to explore, and planets to exploit...it should give it a real role in a combat fleet.