I agree. His music is getting very stale (I actually found his violin concerto to be boring). Minimalism, which is a silly term anyway, is essentially gone. I've known the music of Reich, Glass, Adams, Riley, Young etc since the late 70's, and have interviewed and met all of them during my college years. A shame, since much of their earlier output is amazing. One of the best concerts I attended was the Chicago premiere of Harmonium, conducted by Felix Slatkin, at an outdoor Grant Park concert. Adams was there, and I had a great chat with him.
For alternatives, there is always the music of Morton Feldman (particularly the works from 1977 on, which is arguably his best), some decent work by Charlemagne Palestine (Strumming Music is still the best, in my opinion) and a few others. Not to be self-promoting, but just to show that there is recent music with repetitive structures that I think, are of value, you may want to look at [...] for some examples. Not putting my works in the same class as any of the others, but I'd like to think there's something new and interesting about it.