I'm quoting user samukas as I agree with his request but want to see it done :)
PS- I'm an android user, but i think this is usuful for everybody (android, apple, and even cloudsync)
"Hey everyone!
So, before I begin with my "big request", let me just say that PlexSync is amazing! It is by far a greater implementation than I thought it would be. The fact that the transcoder automatically kicks in when new episodes are scanned into the library and I just have to wait a few minutes for them to transfer to my iPad and take them with me... amazing! KLEXi be gone... forever! 
At the moment, subtitle inclusion is not working 100% so far for some users (myself included I think), but if I understand correctly, what PMS is doing is embed the subtitles (even if they are external SRT/ASS files) in the MP4 file that it transcodes to iOS devices. Is this correct?
If so, I have a small "issue" with this. As many users from non-english speaking countries will tell you, subtitles are rarely released at the same time as the video itself. Which means, right now, that I will end up most likely syncing content withoutsubtitles, and having to manually delete the sync to do it again when subtitles are available. That's twice the workload, twice the bandwidth and unecessary work.
My sugestion is the implementation of a "Require Subtitles" toogle which will tell PMS to only transcode/sync episodes or movies when:
1) The file itself has embeddes subtitles of the language specified.
2) PMS detects and scans an external subtitle file of that language into the library.
Something like this:
I realize this might be a "low priority" request for hearing native english speakers, but for the hearing-impaired and also for people who do require subtitles to watch content, I think this is a really big request. "
