Might require reaching out to http://plexrequests.8bits.ca/ but they already have a nice system for capturing new TV series and Movie requests.. It would be great if there was a way to take these and feed them into the series and discover plugins etc.
Or maybe just build something similar into the web gui?
I dont see that they have a documented api, so the answer as to using it as an input is nope
I have requested my sis and one of my friends who are using PLEX with me, that they manage a LIST on trakt, which I'm checking regularly with flexget and all the movies are downloaded for them, based on their lists... It's easy as "plex requests".