I really agree with some of the ideas in the OP.
Fuel costs:
Fuel is practically free. Surely the hydrogen isn't that expensive, but operating the pumping facility (in space of all places) might be. So I'd agree with a price increase.
Repair costs:
I got my T6 torn to shreds a few weeks ago. I probably had less than 30% left between all my modules combined, and 16% hull integrity left.
Repair bill? 30k.
This is absurd. Unless our ships are made of paper machete, there is no reason a 200t space ship repair bill should be equivalent to 3 slaves.
Maintenance costs:
For whatever reason, people aren't a fan of taking out anything but the largest ship ship they can possibly afford. I don't really get this. I tend to get a lot of flak when I suggest people take out smaller ships.
"But what's the point of big ships if I can't afford to fly them?" Well, you wouldn't drive your yacht to school. No, you save it for those special occasions. Like assassination missions, etc.
However, ED really drops the ball in this regard, resulting in the maintenance cost reduction being necessary. It's not all that convenient to get into your bigger ship after accepting a mission, so people want to stay in it and fly around in their pythons all the time.
So once more mechanics are in place to make it easier to use your big ships without being in them all the time, then I will be more okay with operating costs getting pushed back up.