1. They could underestimate the effort needed. Continously integrating the packages from sid and upstream and the own development effort, all without breaking for the user, without having targeted maintainers per package, is quite an effort.
The mechanisms Gentoo has in place to manage this don't seem fitting for Ubuntu.
2. The half-year release circle gives users a sense of the progress made. Even while using a LTS-release, observing the new releases i can see where Ubuntu is heading to, what is changing and what to expect for the next LTS. The releases give Ubuntu opportunity to talk about their changes.
Not saying it can't work or it is a bad idea (I don't have enough experience maintaining, especially not a distro, to judge). I see the positive aspects and the proposal sounds reasonable.
The packaging is actually likely to be a lot easier, which is one of the big perks to this model. They only get stuck supporting the LTS releases, instead of having to backport fixes to every release in the last X years (was it 4?).
Something to keep in mind is that just because there is an updated package available for something, there is no need to get it updated on day 1. I suspect they've got a good feel for update frequency and priority on various packages. Worse case, they'll probably get it updated and more recent than the six month cycle (or 12 month if you run LTS).
1. They could underestimate the effort needed. Continously integrating the packages from sid and upstream and the own development effort, all without breaking for the user, without having targeted maintainers per package, is quite an effort.
The mechanisms Gentoo has in place to manage this don't seem fitting for Ubuntu.
2. The half-year release circle gives users a sense of the progress made. Even while using a LTS-release, observing the new releases i can see where Ubuntu is heading to, what is changing and what to expect for the next LTS. The releases give Ubuntu opportunity to talk about their changes.
Not saying it can't work or it is a bad idea (I don't have enough experience maintaining, especially not a distro, to judge). I see the positive aspects and the proposal sounds reasonable.