Yes, that would be very helpful, provided Newsbin takes intelligently a suitable substring from the subject.
Or to use the name of the nzb file for folder.
Often nzb files are posted together with rar files, and often the nzb files have the most suitable, most precise names with upper/lower case letters correctly preserved, etc.
So an alternative to a subject substring would be to take the name of the nzb file.
Of course, it is not always easy to determine which nzb file belong to which post.
Sometimes the names are very close, so such an implementation is possible:
some.title.s01e06.720p.hdtv.x264-crimson.rar
....
Some.Title.S01E06.720p.HDTV.x264-CRiMSON.nzb
But, unfortunately, this is the best case scenario.
In other cases, the rar file name might contain additionally the title of the episode but nzb - no title,
or the rar file name might have episode number as 106 while in nzb - S01E06,
or the rar file name might have the release group name at the beginning, not at the end.
And there are cases when the poster offers a rebus to solve, for example (I have to give here the real nzb file name, not sure if it is allowed, if not, please delete it):
the.tale.of.twin.slayers.104.720p-dimension.rar
Ringer.S01E04.720p.HDTV.X264-DIMENSION.nzb
The name is pretty obvious to me, but it might be too difficult for Newsbin to solve