I'm in agreement with most of what's been gone over, here. 3.0 Amanuesnsis is, essentially, the fastest way to copy spellbooks in the game, but that's all it does that's all that special compared to 3.5 Amanuensis. As for the "issue" of not copying pictures or diagrams, I've taken a few graduate-level Math courses, and the textbooks we use are about 80% text and 15% equations with notation. The last 5% are a sparse few diagrams that are supposedly learning aides, but kinda require you to have a good understanding of the base material in the first place to understand them, anyway. If we look at Spellbooks as we would most any other sort of scholarly text in the real world, I'd say that any spellbook that wasn't written by a Geometer could be effectively copied by 3.0 Amanuensis.
Also, as 3.0 Amanuensis is the fastest method of copying spells in the game, and since it's not a spell a typical wizard prepares on a typical workday, anyway, it's exact level isn't actually all that important. It's kinda worthwhile regardless of where it winds up on the spell list if you know that you're going to use it.