> Obviously, a single monolithic spec controlled by a committee like the matrix spec core team has its own problems (most importantly, the committee can become a bottleneck); and we still provide mechanisms to let people experiment via the equivalent of vendor prefixing, which can go horribly wrong (c.f. aggregations in Matrix) if not managed with discipline.

...which is by far the biggest shortcoming of Matrix I'm aware of. I reserve the right to refute the inaccurate criticisms though (and to call them FUD, if that's what they are :)