Possible "major points and findings" (BROAD focus)
@Philippe: it really depends. As far as I know, all have their own specific demands, problems, guidelines and community mentality. However, in general, the process works the same.
As far as I can judge, the German Wikipedia is the most different from the English one. It has a comparable quality level but the machine seems to produce less "dust". In general, their FA articles (last time I looked, they had more than any other project!) are really well-written, accurate and enjoyable to read. Their total coverage is smaller than that of the English Wikipedia though. It is possible the difference was caused because wp-de is older than any other project except for wp-en. When wp-de was founded, there simply was little to translate/compare with yet at wp-en. Also take in mind that wp-de was not just set up as a German version of Wikipedia, but also as an experiment how to build Wikipedia differently.
Other large projects seem to basically have the same machinery as wp-en but with their own specific niches in content and guidelines. Content niches can be language-, geography- or culture-related (i.e. the Spanish Wikipedia will have better articles about Mexican culture or Spanish cuisine), but also otherwise. Excellent articles on general subjects can exist at (for example) wp-pt or wp-fr, while wp-en only has a stub. The French project has developed its own characteristic lay-out; the Dutch project is focussed on maintenance, etc. In general, I find that (apart from wp-de) most projects translated their guidelines and project pages to some degree from wp-en and have therefore more or less the same community and content evolution, all at their own time and pace. They are dealing or will be dealing with the same problems wp-en deals with (but often less severely because of their smaller size). Some projects may experience problems that have been encountered before by wp-en, but have now been solved there (Yaroslav Blanter gave an interesting overview of wp-ru on this talk page, which shows us it experiences problems that seem to be common for projects with 250,000-1,000,000 articles).
Therefore I assume that FT2's 6 points are valuable for all projects. That being said, we should keep the differences in mind. Differences in guidelines can reflect cultural difference. Is sound perhaps cliché, but my own experience with German people is that they have a perfectionist mentality and are in general more interested in materialistic quality. This seems to be reflected in the content of the German project. I found similar cultural influences when comparing the content and guidelines of wp-fr, wp-es and wp-nl. Weather by chance or because of cultural differences, probably most larger projects did invent or explore new ways of doing things. Whenever one project develops its own way for something, we should analyse what happens and use the knowledge to the benefit of all projects. I'm sorry, but the only project where I found contributors that think they are the only Wikipedia is wp-en. I believe this isolationist attitude can in the end be harmful for that project.
I agree with Woodwalker. We have some expertise in projects different from en.wp, and they seem to have many common features, so that the above points are relevant to some extent for all of them.
On the other hand, smaller wikipedias have markedly different problems. For instance, I have close relations with admins of crh.wp and xal.wp - these are the projects with several hundred articles. They are really happy to accept any non-vandal contribution, and they are very far from the state when all "low-hanging fruit" has been consumed. They have more issues like establishing the proper spelling (on xal.wp the four active native speaker participants had a quarrel about the geographic names of countries, and apparently the reliable sources on this subject do not exist in their language at all - and one contributor left the project since his version was rejected). Obviously our point are not valid for such small projects. To help them, I believe one needs to approach them separately.
I am also ashamed to say I do not have a slightest idea on what happens on the projects other then Wikipedia and whether our discussion apply over there.