OK, FWIW:
I just came back from a 200 mile trip using my neighbors 2008 ES350. I did notice, on occasion, a slight flare between the 1-2 and 2-3 shift. The RPM on the tach registered a flare of no more than 200 RPM, which was no big deal, as far as I was concerned, and the owner told me that he was never even aware of it in the 2600 miles on the odometer.
So, in my estimation, this flare problem was never completely corrected in the 2008 models, and as I said before, IT WAS NO BIG DEAL!!!! ;)