The room configurations at the Waldorf vary quite a bit, and I've found it to be hit or miss as far was what one gets. I used to get upgraded to a junior suite regularly, but now almost never.

The exec rooms seem to be scattered throughout the hotel, as far as I can tell.

I guess I slightly prefer the traditional rooms as they have a separate bathroom, but I've had some nice contemp rooms. Personally, I'll take a courtyard (no view) room over a street view, as I've had one too many nights listening to the traffic noise outside the hotel (might depend on the floor you're on). Waldorf is not the place to stay if you want any kind of view.

I have found that they are quite accommodating in changing your room, if you ask. Of course it's based on how crowded they are, but if you're not happy with the room just ask to move.

All in all, Waldorf is one of my two favorite Hiltons in London (Trafalgar is the other, which may win out marginally).