We were in the Blue Mts. last Wednesday (Oz time), it sounds like a day before the OP. We had the same conditions although it cleared enough to get a good view at the bottom of the Scenic World tram and inclined RR. We never saw the 3 Sisters....the clouds drifted around and we saw everything else but 3S. The guide gave the group a choice of waiting around at the bottom or continuing up to a viewpoint above. He felt staying put provided a better chance, but the clouds never cooperated. At the falls it was clear and sunny so we had a great look around!

Thursday (when OP presumably went) was fairly clear and dry in SYD so we thought in retrospect we should have gone a day later...doesn't sound like it made any difference. We were still happy we went, we had excellent weather the rest of the trip (and missed some very bad WX in Melbourne), and this gives us a reason to go back to Oz!