Military or Civilian?
We have a clear distinction between Military and Civilian ships - mostly so that we don't die in micromanaging a bunch of civilian ships. Whilst I generally agree with this, some separations seem to me to be too arbitrary. I was wondering if we could change how maintenance is calculated for engines. At the moment we have a clear distinction: Any engine below size 25 is military, any engine above engine power x0.50 is military. This leads to most of my designs being at the opposite side of these spectrums - very view engines are someplace in the middle.
So how about maintenance below engine power x0.50 stays at zero, then from x0.50 to x1.00 it increases linear and from x1.00 onwards we have the same calculations as we do now. With this linear grade, we could gain the additional option of "fast mid-range transports" that do need maintenance but have superior speed over the non-maintenance transports. Or also some kind of "lower maintenance small military ships". I think adding this option might open up some design options... .
I don't know if doing the same kind of grade with engine size would make sense. But I think it would with engine power factor. All ships from x0.55 upwards stay military, but between x0.55 to x0.95 they have a lower maintenance need... .
This already happens to a degree, because EP modifiers below 1.0x apply as a multiplier to the cost in addition to the usual behavior. So if you have, say, a size-20 ion drive (12.5 EP/HS), at a 1.0x multiplier your engine has 250 EP and 125 BP cost. As a 0.8x multiplier, your engine has 200 EP but rather than the 100 BP you would expect, it is only 80 BP because the cost is additionally multiplied by that 0.8x. Since maintenance cost is tied to BP cost this also affects maintenance requirement.
Midrange EP modifiers do already have their place, for example large engines with sub-1.0x multipliers are useful for large capital ships to reduce fuel demands, MSP consumption, cost, etc. Another example is that frequently a multiplie of, say, 0.75x is good for survey ships which already have maintenance requirements, to allow faster surveying but still sufficient fuel efficiency.
Basically I would worry that applying an additional modifier for 0.5x to 0.95x multipliers will open some rather exploitable design space with designs that already have a valid place in Aurora. The current system may be a bit questionable in its verisimilitude but it does work quite well for what it needs to accomplish.