[murkt]

You can make the feature with one colleague, or you can call in five more people to weigh in and do their parts of the work.

If you involve five more, the result could be better in theory, but it will certainly take MUCH more time because of communication overhead.

[munk-a]

Pretalking is highly valuable. Making sure that key stakeholders have an aligned vision and are invested in defending it before opening up a discussion (or dictate, depending on the culture) to a wider audience is necessary. Occasionally expect that the stakeholders and you got it wrong and you'll need to invest time into rebuilding the solution, but, if you're honest with yourselves and diligent, assume that generally the expert subgroup will supply a comprehensive solution.