1. the mining ship is designed to crack big asteroids that you can find at random locations in mineable fields. It has no effect on small rocks but will if done correctly destroy the large rocks which contain large amounts of "whatever".
2. ok... you got a point with the 200bot/bats limit... but it should be no problem to raise that limit
and yes it can repair other ships
just like the mining ship the repair ship is not designed to shoot on small targets but to be a utility ship to support large ships and fleets
thats why the laser is fixed