Spaceflight companies (SpaceX, ULA, etc.) make profit by launching satellite/cargo into space. They usually receive fully assembled satellite and all they should do is to just design a rocket that can place that satellite into the designated orbit.
I think there should be a mod which enables satellite launch contracts to provide different kinds of pre-assembled satellites that vary in weight, size and so on. Heavier satellite will require a stronger engine and more fuel to burn which increases overall cost and difficulty in designing a rocket.
I don't know much about the coding behind the satellite contracts but it seems that the location where the satellite should be sent to is random. Isn't it reasonable to have high demands of satellite launches into the orbit of Kerbin and less as it moves farther away?