Jesper, on the abstract decision model side of things, let me share my
understanding. Note that I'm specifically not speaking for the project
as a whole, just the way I think about things.
In practice, we generally use a loose consensus model. We don't require
full consensus, but we do require there to be a) an agreement on
direction being generally valuable to more than the contributor, b) a
lack of strong objections from established contributors, and c) an
(often implicit) commitment from the proposer to invest enough effort in
the project to justify any downsides other contributors might experience.
Point (c) is frequently where a lot of large proposals from new
contributors fail. Unless there's someone else strongly motivated to
drive it forward who can step in to satisfy (c), then a proposal is
likely to die on the vine. Some of the most important feedback any
proposal gets is about how to reduce the cost to other contributors. If
that feedback is ignored, then the proposal is almost certain dead. (I
see this all the time.)
Point (b) is a major stumbling block, but can almost always be worked
through. There's a couple of implicit points worth noting. 1) We
require that objections be largely technical in nature. 2) Anyone
objecting strongly is expect to be themselves a long term contributor
whose been through the process before. 3) There's a lot of horse trading
which goes on behind the scenes, and 4) because a strong objection is so
powerful, it's frequently waived. Objections based on (1) can
frequently be addressed through offline direct conversation, and
frequently lead to revisions in proposal. (Usually, a reduction in
initial scope, sometimes the opposite.) (3) is a practical necessity as
no one has the time to review and think through *everything*; I'm much
more likely to invest time in a proposal coming from someone who I've
worked closely with in the past than a stranger. (4) shows up in subtle
ways. If you've seen me or someone else say something to the effect of
"Drive by comment", "minor concern", "deferring to X on point Y", those
are all indications that I've chosen explicitly *not* to express a
strong objection.
Point (a) may seem like the core point, but it's generally the easiest.
Once (b) has been addressed, (a) almost always follows.
Again, speaking only for myself.
Philip