Negroponte himself has always been a politician, a hypester, and a sleaze. His one true innovation was in fundraising – he was able to get industries that weren՚t used to funding research (eg the newspapers) to pony up for industry consortia. This was, maybe, better than the usual DoD funding that kept the AI lab alive, but it came with constraints of its own, including trying to impose IP agreements on the graduate students that made it difficult to open-source software. And of course in later days (I was mercifully gone by then) the creative approach to fundraising ran into even more serious issues with Jeffrey Epstein.
I՚d say evaluations of the Media Lab as an institution should be done separately from evaluations of any particular program or researcher who may have passed through there, because while the institution has some fundamentally broken aspects, there has been a lot of good work done there.