suspiciouscoffee said:
In the autobiographical screenplay I'm drafting, the main character (who is me) is unnamed. I'm doing this to further express the theme of isolation, and the exploration/creation of personal identity.
But it seems pretentious and dumb when I do it.
Stylistically, anything unusual draws attention to itself. The question is only if it's the sort of attention you want.
Aside from the other examples given so far,
Ragtime used generic "Mother" and "Father" names for characters to emphasize the idealized homogeneous nuclear family. That worked okay because the entire novel was engaged in wacky experiments with convention, and that was just another one on the pile.
Half Asleep in Frog Pajamas was written in second person, and that was very unsettling throughout the entire book, but again being forced out of your comfort zone may have been the point. I remember
Jasmine did a cool thing with dissociative states where a character who was in shock after a bombing described another woman screaming at first responders in a murderous tirade, but careful reading indicates it was herself -- the style choice telling you that the attack broke her mentally.
For a book, not naming the main character may not actually be that noticeable most of the time if written in first person, would be very noticeable in third person, and would be completely lost in the freakshow that is second person. For a play, I'd say you're somewhere between first and third.
I think your worries about seeming pretentious are overblown. Also, it's a screenplay -- you're already soaking in it! In short, I think using unusual stylistic choices to create mood/atmosphere is completely legit. Your only risk is that an author ultimately has no control over how their audience interprets their work.