I dunno, I kinda think he's full of xxit. His designs were "radical", yes, but I never really liked them. I think a lot of others feel the same way; BMWs designed during his tenure have sold well despite their looks because they have so many other merits.
In terms of his work moving the auto design industry forward, maybe so... but it took a LOT of tweaking to bring his designs to a point where they were attractive.
Earlier generations all looked great to me from the moment I saw them. Taking the 3 series as an example, previous redesigns were not what I would call "radical", but I definitely think the e30-->e36-->e46 were all excellent evolutions that resulted in some of the best looking cars on the road in each of their days - which have stood the test of time. The same cannot be said of the e90, in my opinion.
Fortunately, the 3 series has it's stellar looks back again with the F30 - now that Bangle has been put out to pasture where he can't do any more harm. Funny that he's now critiquing the auto design industry as a whole; just because there are no radical designs that intrigue his fringe aesthetic, he thinks that signifies a design rut. I think there are a lot of great looking cars out there from a number of different manufacturers, and I for one hope Bangle remains in retirement.