I have very faint memories of what the Renaissance Center and Trappers Alley looked like before the 2000's when one was renovated by GM and the other became Greektown Casino.
The more I read about Trappers Alley, the more I feel it's a shame it didn't do well because the idea of a multilevel marketplace seems so distinctive and original, at least for Detroit. The casino pushing in seems to bring in a bland generic modernity instead of something more historical feeling.

As for the RenCen, I think I was in there once before the renovations started and it felt like a bunch of crooked hallways that made up a maze. I've been there recently for Youmacon but as a kid, it didn't feel like there was as much open space on the lower floors and there were many more stores in the building. I know the wintergarden didn't exist and I know the glass circular walkway on the second floor also is new. [[I also know about the berms outside that were removed)
But does anyone remember what else was changed or better have pictures to show either?