Taking each theory one by one:
-Frequently reviving a show isn't on its face a bad thing- The Glass Menagerie is revived a lot, but each production has a lot of buzz and interest (even when it's not directed by Sam Gold).
-I don't think the theater is a problem- the St. James is a historic house, and when I saw it over the weekend the orchestra and most of the mezzanine were filled (they're not selling the balcony, but that's common practice for plays in large houses- Sweat is doing the same thing with rear mezz)
-Kline is seemingly still a draw- the audience I saw it with gave him rousing entrance applause and a standing ovation (admittedly they looked like mostly tourists with TDF tix)
My money is on number two- this is an extremely strong season, and with so many musicals and plays commanding peoples' attention, some shows are bound to fall through the cracks.
That being said, I absolutely loved Present Laughter (went into detail on the previews thread) and I highly recommend it!