The script’s unevenness does make you wonder, though, how Hansberry might have reworked it if she’d had the energy, and the privilege of time — and to what degree she, a Black woman and closeted lesbian in the very white, very male, ostensibly straight world of midcentury American theater, felt pressure to conform in her playmaking.
Because really? Sidney Brustein, whom she has placed at the center of this crowded tragicomedy, is not an interesting person. This is not Isaac’s fault, although he ignores Hansberry’s stipulation that Sidney “laughs at himself as much as the world.” Isaac’s performance is mostly unremarkable but fine, sparking fully to life only in Sidney’s scenes with Iris’s wealthy, conventional sister, Mavis — the best role in the show, and the best played, by a thoroughly captivating Miriam Silverman. (The play is a Tony nominee for best revival; Silverman is its only acting nominee.)"
(Green's review of the production at BAM is here: https://www.nytimes.com/2023/02/27/theater/the-sign-in-sidney-brusteins-window-bam-review.html)