I partially disagree with that. First, I think you mean "you can do the highlights of the AR side" in a day. You didn't do all of this:

Lower Circuit
Upper Circuit
Devil's Throat
the island (was it open?) by boat
the boat ride into the mist
the mile-or-two each way hike through the jungle to the standalone falls (in the opposite direction from all the main trails)

during one day, did you?

Second, easier at the time year you were there than when I was there. It was very hot in the middle of the day (late Nov/early Dec), so I was very glad I had the time to stay inside for a few hours at the middle of the day and just be out on the trails through late morning and then again from mid-afternoon.

Third, it sounds like you either had luck with good weather the whole time or didn't care. I wouldn't consider it doable in one day if that one day is overcast or raining, given that I think you haven't really done it if you haven't seen rainbows at several falls (which can only be done when the sun is out and only at certain times of day for each location). I did, in fact, do the BR side twice (though each time it took well less than a full day) because the first time it was raining and then the next day I had better weather. (Note: I was going from the BR side town in that case, not from the AR side, since I flew into IGU but out of IGR.) The views from the BR side looked so much better in good weather than rain -- although you could grasp the expanse of falls, if that's all your after, in rain just as easily as in sun -- that I'm glad I allocated extra days to allow for weather.

And what are they constructing now??? I read about upgrades being done to room before I went (last Nov), then I noticed/heard no construction last Nov (I was on the first floor or ground floor the whole time, though, except the couple times I went up to the roof terrace from the third floor). So is this a continuation/resumption of the room upgrades, or something different now?