Having a greater range on the FSD is not going to make an appreciable difference on longer exploring trips, so your conclusion about removing 'the tedium of honk jumping' doesn't hold up.
I have a feeling that a moded module will brake easyer and malfuntion more amd probably require more power, give out more heat and waigh more or some combo of these things depending on what you change.
I base this on the comment the braban said about the helicopters in vietnam being modded to take off quicker but as a result braking more. (And my hopes and dreams)
I also think that some modds will be RNG so ya never quite know what ya gunna get
I'd be livid if I did the same work to get modded thrusters as someone else, for the same ship, and theirs is better because luck.
It is highly unlikely that RNG will play a role in the Engineers' upgrades. They are being individually created, and there is a limited number of them. What is available to individual players may vary according to the players' standing/rank/allegiance.