Can I request that Dorico takes into account accidentals in bars before repeat ending in deciding cautionary accidentals in 2nd, 3rd, etc. time bars.
You can request it, of course. It’s already on our backlog and has been since long before any of you got your eyes on the software. In the future we plan to try to take care of all of the various bits of musical state that can change either side of a repeat barline or repeat ending, including clefs, key signatures, time signatures, accidentals, and ongoing items like slurs, lyric lines, ties, glissandos, and so on. But that is a big and complicated job and not one that we anticipate tackling in the immediate future.
I have no doubt of your thoroughness… 
Thank you!