I'm of two minds when it comes to things like IE and ancient dragons being given statistics. On one hand, having a skill of 6 represents nigh-mastery of the skill in question. There's the odd person who can surpass it and get to 7 (via quality), but that represents having insights that leave even the masters in your wake. On the other hand, having ages to refine and hone a skill set might in theory put you higher -- but without the mental and physical capabilities to retain what you've learned and developed, you're going to forget as much as you learn. The 'brain full' scenario.
While I can understand the intent behind something like 'Sorcery Group 12', I'm thinking it would run better through attributes over skills. A character with impressive attributes gets larger dice pools overall, you don't need to break the 'max 6' rule to make them impressive. Lofwyr, for example, has Will 24, Magic 27. Just looking at that, you know his dice pools are impressive. An extra 6-8 dice added on will be almost a drop in the bucket - and this makes sense. His knowledge is vast - but his capability of
retaining knowledge is what sets him apart. An Immortal Elf, I can see having mental attributes in the 6-9 range, maybe even tipping into the 11-12 range, but their skills would be limited to the 5-7 range, which makes sense. They'd still be impressive, and powerful, and in a one-on-one fight they're very likely to win against most normal opponents - but their edge is in experience and cleverness, not in the 'I'm stronger than you'. You don't beat an IE because they've got plans within plans and contingencies for everything you throw at them, not because their statline's necessarily better than yours (though it helps).
Now, if perhaps someone who's ancient and knowledgeable is somehow capable of removing the cap on skills, then maybe. If it was something like 'when 100 years you hit, your limit goes up by one, then 200 years after that, then 300 years after that, etc, etc, drek etc'. So a 600 year old elf might be allowed to have skills at 9, a 1000 year old elf can have skills at 10, 1500 years is 11, 2100 years is 12, etc. I could see something like this being in the rules - and not mentioned since no PC is going to already be that old.
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That said. What I like in game books? A blend of crunch and fluff. I liked the original Tir n'an Og book (sp?) because it had a lot of interesting stuff in the front end, and gobs of crunch in the back end. (I wish the Path of the Wheel would be fully reprinted for 4E. Honestly...) The Tir Tiarngire book disappointed me because it had nothing in the back - I was hoping to see some of the advancements that the Tir had, but got nothing for my troubles. I think the former book was the first introduction to bioware (which was cool), and the morph-seeking rifle was pretty awesome as well.
So, books with more tech, metamagic, totems, echoes, etc, are always a plus in my books. A setting book detailing what the setting is like, and then some of the stuff to be found there which makes it unique, is always cool. Advancing the technology and magic of the setting, letting it creep forward from time to time, is excellent. It was why I was interested in Spy Games and War, actually -- I had always wanted to see the covert and military side of Shadowrun. I'd love to see a proper mercenary book, with details on how to run full-blown Merc campaigns. I want to see advancements in robotics, and linear frames, and anthro drones. Details on the metaplanes and deep resonance would be cool, too.