Only point of disagreement is that for game design, I say pick one magic "story" and stick to that for your campaign. Proliferating magic-explanations are unnecessary complication. For me, Vancian book-magic is all I think necessary.I agree and disagree with this. I have no problem with variant forms of magic per se, especially since in both fantasy literature and in real world beliefs about magic, multiple varieties of magic are pretty common. I see no problem with having one group of spell-casters use knowledge of magical forces to cast spells, while another asks for supernatural assistance. Even in terms of just the Magic-User class, you have multiple forms of magic: spells, two kinds of single-use magic items (scrolls and potions,) and reusable magic items (rings, wands, etc.) Each has its own rules.
But these different varieties of magic all use a single system: effects are rated by level, character level limits which effects are available, new effects must be researched, and in most cases the victim gets a saving throw. There are a few tweaks to clerical magic compared to M-U magic, but both work basically the same. That's fine with me.
What would bother me would be multiple magic mechanics. That's another reason why I don't like the psionics system as it is usually presented: despite the different name, it's really another form of magic, and it uses entirely different mechanics. If those rules were presented as an alternative set of mechanics, instead of an optional (but additional) set of mechanics, it wouldn't be as bad; even better would be a psionics system that follows the same mechanics as other magic, with a few tweaks to make it feel more like psychic powers.
The way I see it, a very small number of common magic systems that use the same mechanics is fine and in many cases desirable. You don't want too many common forms of magic, but there could be additional forms that would exist in isolated geographical regions or available to secret societies. The trick is not to overwhelm players with too many options. These systems should be designed as true variants of a central set of mechanics, rather than as completely distinct from each other.
Unique spell lists seems perfectly acceptable, although I think there should be some additional changes to the way the new form of magic works beyond a mere shuffling of which types of spells are available at each level. This was the rationale behind my suggestions on how illusionist spells should work: I wanted illusionists to feel different, beyond merely being able to cast illusions at a lower spell level than ordinary M-Us.
I may have more to say about this in the future.