His sonnets were also tinged with an intense emotionality more reminiscent of ENFjs than INFps. However, also within his sonnets one may see time as a reoccurring theme and this may point to Ni being stronger than Fe. I am still undecided, although I do lean more toward ENFj than INFp at the moment.
If you look at INFP poetry it is pretty much always based on the emotional situation. You see, poetry is often how INFPs express Fe, because unlike ENFJs, they are a bit unsure of it. I don't think I've ever wrote a poem that wasnt based on "intense emotion". I think INFPs can easier get lost in writing a story like shakespear does and can get lost in those emotions the characters experience very easily. Also, the thoughts of the characters, the way Shakespear has them thinking, it truely seems like they're coming from an INFP mindset. It's hard for me to explain...
I think INFP poetry would also be more metaphoric due to Ni as a base an Fe as a creative. At least for personal poems... an ENFJ would be more revealing, as they are more confident about their Fe... they wouldn't feel the need for all the metaphors and have all the confusion in their writings as much.... it wouldn't be as apparent.... their poems would be more blunt, more out there, less metaphoric, more of what would make an INFP feel like their insides were cut out if someone were to read it.

I think many of the emotions he depicts in his stories he has felt himself, or he lost himself so far in the story that he can feel them so realisticly, which is not hard to do for an INFP, and I think that the extremely metaphoric style he uses in order to show those emotions is depictive of an INFP approach to poetry.