Interesting report, but I note that almost all of your comments are on the practicalities of the Sienna and there is very little on what is like to have to drive the thing.
I've not driven the current generation Sienna, but I did sample its predecessor. Whilst it scored highly in matters practical, it was one of the most alarming vehicles I have driven in recent years thanks to steering that is so ridiculously light and devoid of feel that I was convinced that only telepathy connected what you did with the steering wheel to the road wheels. Coupled with dreadful understeer and brakes that made you wonder if the thing was going to stop (and it had only done 2,200 miles so they were not worn out), it was not good for the driver at all. For that reason alone, I would prefer literally any other MiniVan......... I've not driven the latest Honda Odyssey (they do not seem to have appeared in the Hertz fleet), but the previous model, which Hertz had for a while, was so much better to drive and equally practical, that it would be my choice if you could find one.
There must be plenty of drivers who do like completely feel-less steering, as every Toyota I've driven in recent years seems equally cursed (though the Sienna was by some measure the worst culprit), and it is a trend that is afflicting more and more everyday cars from other manufacturers.