Right. Me, I tend to simply treat magic as an excuse to give my characters superhuman powers and I tend to take a "the more the merrier" approach to it. Anyway, I think I basically get your magic system now. It should be fine, but I still think you should consider perhaps simplifying and streamlining it a bit - mainly because you don't want to have to spend a lot of the story explaining all the fine details so the readers can understand how it works, rather than actually telling the story. Note the mild confusion and misconceptions I had from your initial description due to a few ambiguities. That's something you really want to avoid.
It depends on how the magic is used as a narrative device. As I see it, the main purpose of complex magic systems is to have a clear and consistent idea of what magic can generally do and what the requirements for using it are. If you can then integrate that system with your setting and plot, it makes magic easier to use for storytelling. What this amounts to is: The level of complexity of your magic system should serve a purpose in the narrative. (Just like most things in writing.) So, in general, I'd say that the more specific the rules of magic are, the more clear you want to be on how it all works. For example, I don't really need to know exactly how magic works in Lord of the Rings because Frodo doesn't need to know how magic works: He just needs to get the damn ring to the volcano. Magic in that setting is supposed to be mythical and mysterious, fairly rare, only only affects the plot indirectly. The vagueness here is preferable because exploring the mechanics would only be a distraction. On the other hand, Harry Potter magic is an example of a far more specific system that I personally think may have needed a bit more thought put into it. Here the main setting is a school for magic in which the main character is a student. That implies that understanding the principles of magic should be important to Harry, which also makes it important to the readers. In this case it was actually the vague parts I found distracting: I kept asking stuff like: "Why do they need to speak fake Latin in order to cast spells? Like, why is that particular language magically conductive? What is the significance of a personalized wand? Why can't they conjure or transmute food? Why do muggle-born spontaneously display magic talent if it's also heritable?" And so on. (Of course, this is a bit subjective: Not all readers are going to be as analytical about these things as I am. But I like to think it's still worth putting that extra effort in.) It's a bit of a double-edged sword: A more specific magic system is easier to work with, and clear rules ensure that the readers understand what's going on. But if it's too complex, you run a greater risk of introducing inconsistencies and/or the readers getting confused. You want to strike a good balance. So, I'd say that a system with very specific rules should also be as simple as you can make it, that way there's less to keep track of. That's really difficult to answer because good titles tend to have some sort of thematic or motif-based relevance to whatever the story is about. It's hard to say what would be a good fit knowing only the basic premise and some setting details. It's also not something you need to be in much of a hurry to decided on. If you think about it, you could write the entire story before coming up with the title since it won't really affect the rest of the writing process. For that matter, doing so may give you some insight into what to call it.
Damn, you've put exactly what the problem was with Harry Potter so brilliantly! It always struck me as odd as well but because the story was so character driven, I didn't really focus on the magic system involved. I always thought there must be something wrong with *me* that I thought something was "off" in a book everyone else raved about.
