Actually, little of the Pei Plan came to fruition. The Myriad Gardens and a few minor office buildings. The proposed Galleria Mall was supposed to be on the site that will now be Devon's headquarters. The hotels were not built.
But the Myriad Gardens alone were a good product from that. We lost a lot of the historic downtown though, and so a lot of people look at the Pei Plan and 60's Urban Renewal very negatively.
Here's a newly approved project. This is the new pedestrian bridge over the new I-40 re-route south of downtown.
Designed by Hans Butzer, who designed the Oklahoma City Memorial.