Aaaand,
Here we go again!
Re "what makes AM AM" I think I've said mine in a previous thread.
I loosely outlined more complex auras in another, but not a specific system.
As for books vs pdfs vs evolving electronic editions... I love physical books. I buy these. I don't buy gaming pdfs. I love Pathfinder's searchable database. D&D4 had continually changing rules via digital errata, which made the books pretty useless pretty quickly; to stay up to date one needed a subscription. This did not destroy the market for the game iirc, even though the WotC website was painful to use, at least during the free evaluation period when the game came out. A subscription with a good app and search engine is plausible, though I would still miss physical books. (Cue BtVS quote from Giles about knowledge being smelly.) Artwork would mostly get in the way here, since moving more bits around --> wasting more compute/download/render/retrieve/etc time and valuable screen real estate.
As an aside about artwork, some months ago I finally bought the new edition of Nobilis along with the last few AM books, and padded my order with some other gaming books I had heard about. To my surprise, the book I have spent the most time with was the one I expected to be the least interesting: Anima. The artwork probably swayed me to some degree , and I am apparently not immune to such things. The art works well for my physical copy; I have since seen pdfs that load painfully slow. I enjoy that artwork too, yet would prefer it gone. And using the pdf as a reference isn't much fun, since pdfs are really not optimized for the screen (since they reproduce book pages, which are not the same thing at all, even if a screen is large enough to display a page with high quality.)
One thing that I think D&D4 got right, at least to some degree, is that NPCs and PCs are different, and can still work even if they are developed using different rules. In AM, I think something is lost when all creatures are developed according to a single set of rules: Weird powers become difficult because there is a fixed set of rules that have been (vaguely) balanced to work with PCs. For example, I had always assumed that when the canonical Magic Wolf becomes a pack, none of the wolves need to penetrate with their attacks. But that's not so, because of the general rules for MR. A creature's deadly poison is built as a power, so it has to penetrate (but a cobra's does not). The weirder powers are impossible to build. Rules for NPCs of this kind get in the way; maybe a different kind of rules set would serve better. The game is about wizards, and wizards are different from other people, so who needs the same rules if the game works better?
Age and wizards: The ancient wizard is a trope, but so is the wizard or witch who enjoys unnatural extended youth (usually due to some ancestor or nasty undertaking). I think it would be cool to have a wizard's appearance reflect who he is and be utterly unrelated to actual age. You're a studious Bonisagus or a wise and trusted Guernicus mediator? You start to look older and wiser faster. You're a flirtatious Merinita or Jerbiton troubador? Young. And so on. Extended shifts of personality or activity can change appearance, and maybe Twilight Scars involve both changes in appearance and required evolution in personality that cannot be undone (decided by the player, of course), representing the development of Essential Nature (an idea that is associated with the Magic Realm) that begins to subsume the essential choice and malleability of humanity.
Got to go for now.
Anyway,
Ken