I'll repeat my two from the 5.7 thread:
Give us tech to improve the support functions of ships like engineering, life support and bridges. These are fairly common items where reduced sizes/increased efficiencies would help out. Most other items can be teched up for improved efficiency (industrial modules, engines, etc.) so it's a bit odd that these are left out. I purposefully left out fuel storage as we already have the increased fuel efficiency tech which serves much the same purpose, but it could certainly use it too with the new fuel consumption rules.
Second, have ships moving at a reduced speed burn fuel more efficiently. Currently giving my escorts a greater speed with a larger power boost is a bit of a waste if they're normally traveling at the slower fleet speed. If you averaged (or did something similar) between necessary versus max power it would greatly improve fuel efficiency on high-boost engines that are used only occasionally at max speed. It would also allow more "patrol" type ships that run more slowly while deployed but can boost to high combat speeds when necessary at a cost in overall fuel efficiency. As an example, a x2.5 power engine uses x9.88 more fuel (than a x1 boost engine). If you had the ship run at half speed it only needs a x1.25 power boost for x1.75 as much fuel consumption. An average then would give you x5.815 as much fuel per engine power hour, a very large increase in fuel economy. A x1.2 boost engine (x1.58 fuel) running at half speed for x0.6 boost (x0.28 fuel) would give a fuel efficiency of x0.93, not nearly as large of a difference. The speed would also tend to be rather slow when using a low-boost engine in the first place, making half speed much slower. It's interesting to note that a very high-boost engine can't get even close to the fuel consumption of a low-boost engine no matter how slow it goes; even if you take a x2.5 boost engine down to, say, 0.2 boost (we'll assume 0 for the consumption), the fuel requirement is still x4.94. Overall this would help high-boost engines that go at moderately slower speeds the most which is where it's needed most.