I visited T5 last week and I thought that it was amazing....
The sheer size, the natural light and the views must make it one of the best terminals in the world. I think that it's "minimal" design is based on the practical need to process millions of passengers, but also a place to enjoy whilst killing time waiting for your flight.
Like the idea of no floors reaching the sides of the building, giving the impression that they are floating and so maximising the light from the glass shell.
I guest you must see it to make your own opinion....