Matt at Dotage has an awesome run-down of the buildings that have been demolished at Laclede's Landing over the years: Link
Very sad to see. I remember the demolition of the Bronson Hide Building - It was right about the time I had first taken a serious interest in preservation (which was spurred by the demolition of the Ambassador Building), and of course, losing the Switzer Building to storm damage and the Fresh Warehouse to fire was extremely unfortunate.
To me, the most egregious losses on the Landing have come at the hands of Pinnacle/Lumiere. First Street, with Mississippi Nights, Harpo's and other establishments was a great little strip, and was really the Landing's lone connection to the North Riverfront area. The buildings were perfectly viable and a St. Louis institution - Mississippi Nights - was lost. The northern portion of the Landing is basically a dead zone of parking lots now.
In order for the Landing to truly thrive, everything that' s been lost over the years will have to be replaced at some point. Wouldn't preservation have been an easier option?