The reason scientists don't blog a lot, or comment on blogs, is that there aren't reputation metrics associated with that kind of contribution to the scientific canon. It is the same reason that scientists don't share their data-sets. It is work to blog, and to prepare data-sets for public consumption, and there is no reward. If we reward scientists for sharing their comments on each other's papers, and for sharing data-sets, more scientists will be incentivized to make these kinds of contributions to the scientific canon.
The same goes for speed. When the journal editor asks a scientist to peer review a paper, the scientist accepts the request out of a sense of social obligation, but immediately that job goes to the bottom of her list of priorities. She will get no credit for doing the peer review, and so there is no reason to do it quickly.
This de-prioritization of peer review slows down the whole scientific communication system. To speed it up, we need to incentivize scientists to share their comments quickly. If someone sees something wrong the description of an experimental set-up, the system needs to be set up in such a way that they are incentivized to share that insight quickly.