I'm of course totally on the outside in regards to what the intention was with the idea of submitting magus characters. But seeing as how this is the discussion forum I thought I'd put up my thoughts for discussion.
Putting the spells around a single character forces the spells to be practical. The author has to think "Would Jimbo invent this spell?" and "What spell would Jimbo want at this point?". The spells have to fit with the character's art scores, this method forces the author into the mindset of a player.
Putting the spells and items around a character gives the reader a view of what a magus should look like. from the perspective of how to grow a character. I've had players in my games that never really looked at their magi with an eye to what the magi would want to achieve. The players in my last game did not have this hang up despite the fact that 3 out of the four of them had never played the game before because I made them all run through at least a dozen years of character advancement forcing them to figure out how to use their character's particular magic to defeat obstacles. This format would let a newbie see how to think like a magus.
Putting the spells in context with one another allows you to create spells that interact with one another. In my experience characters don't develop spells to function alone as much as they develop spells to function with other spells. The last character I played developed high level intellego mentem spells not just to use on low MR targets at AC range but also to ping the powerful nemesis of the covenant at that range so the ghost would scry on my magus and thereby open himself up to the combo of invisible eye revealed and peering into the mortal mind. Look for an old thread by Badger 101 on this board called Grimore of the wolf pack (edit, here it is: Grimoire of the Wolf Pack: Mid-level spells for moderation). It's not about a spell that creates a wolf or a group of wolves. It's about controlling the pack of wolves that you've not only created but also enlarged, metamorphosed their fur into steel and given the ability to soar like eagles. It's all about the Rube Goldberg machines of awesomeness, you can't get that with a spell list.