I think the answer is -- it depends. Kruchten defines the 4+1 views, which are covered somewhat in the default EA views. There are other "Views" that may be useful for your process, or if you choose to follow someone else's definition of a process, they may have additional views.
I have found that how you organize your model depends on 4 major factors:
1) what "views" are important for you -- tied to some kind of design process
2) code generation -- if you use it, organize things wisely...especially if the code uses packages as namespace
3) documentation generation -- if you use it, also organize things wisely, because this can really help you not have to completely reorganize everything in order to generate good documentation out of the model.
4) Version Control strategy -- if you are going to have multiple people work on it...you need to organize things wisely to allow it.
I think it takes time, learning/experience to get good at this and have a good vision for how to organize it and break up the work. Initially, a lot of stumbling occurs and bad organization, etc., but as you continue to work -- things get more clear, and a cleaner picture evolves. I would definitely keep those four things in mind, though, as they tend to be some of the bigger driving factors.
