Re: The snag with a four-week release cycle ...
I work to a fortnightly release cycle and there is no difference between a fast release cycle and a slow one:
1) There is still pressure from the PM to get commits into the next release instead of the one after that, even though it will result in bugs being opened later because it's been bodged together to meet the deadline.
2) There are still such things as dependencies.
The only difference as far as I can see is that with a fast release cycle these problems happen every two weeks instead of e.g. every six months or year.