Steve Benton's Spatial Imaging Group and its student diaspora had a huge influence on the holography and 3D display world. We developed full color reflection holography, the first holographic video system, and the first image predistortion algorithms for light fields. Our 1 meter sq hologram was at the time the world's largest computer generated 3D display. Unfortunately, Steve died pre-Google, and his contributions are not fully recognized.
I was at the lab a long time ago (from its opening in 1985 until 1997). What made it unique at the time was breaking down the barriers between computation, technology, creative arts, and popular culture in a way that seems so natural now. On a campus where hundreds of other PhD students seemed to be working on amazing research on very detailed topics, we were building pieces of the future and demoing them daily to industry and lay people alike. That wasn't considered hard science at a place like MIT, but the ultimate impact on society was huge.
One other area of huge but unsung impact was speech technology. Chris Schmandt's Speech Research Group group envisioned and developed audio assistants that paved the way for Siri and Alexa. His students and research have also helped shape an entire field.
As for current controversies, well after my time. The big deal about funding back at the beginning of the Media Lab was taking corporate money vs government/defense money (90% corporate for the ML vs 90% government for the rest of MIT).