Cost vs Benefits of Wikiprojects
Dear Jorge Stolfi,
If I assume that the goal of a project is to create FA or GA articles, and assume that FA and GA are good indicators for the amount of quality, than I agree with you. However, I don't think either one of those assumptions is necessarily true.
The task force for quality has recommended to bring the Wikiprojects of diferent Wikipedias together. The reason behind this is not to stimulate the production of FA articles, but to encourage discussion and enquiry. The projects should be the platforms where specialist users meet to find areas where the coverage is lacking, answer questions from other users and try to give their work some direction. Also, they should try to establish what aspects like "verifiability", "balance" and "neutrality" mean for their particular field.