That play call to throw what amounts to a jump ball to an undersized receiver who has little experience was dumb and vintage Roman. Lamar should have not forced it, but again, imagine if the Ravens had a Hopkins or someone like that- then plays like that would yield something. But they don't, and they still do it, just because.
As for the "regression" in his overall game- I think its a combination of things- the Ravens no longer have a dominant OL(mediocre at best), his targets are even more limited than last season, defenses defend them better, he is pressing and trying to stay in the pocket more(too long at times), and last but not least- a terrible and vanilla scheme that almost never creates space.