I like the larger variety of skill levels. Though, the "Ten Days To Become a Legend" wouldn't be quite fixed, at least it wouldn't be so glaringly obvious.
I, personally, think that skill levels should be much more difficult to obtain, to the point where it gets exponentially hard to become legendary. Increasing skills should also require a bit more variety in a dwarf's activities within that skill.
For example, a dwarf who makes nothing but mugs all day will start seeing a plateu on his skill increases, while a dwarf who creates more of variety of stone crafts will, after a while, become more skilled faster. The same applies to miners: A miner who does nothing but dig dirt all day won't get better at all, really, but one who digs out a variety of rocks fifteen levels below the surface will "skill up" much faster. Same applies with engravers: If they do nothing but smooth granite floors all day, then they'll see a plateu, but if they smooth a variety of rocks and then engrave them, then they'll skill up much faster. (I think engraving and smoothing should be different, though, but that's just me.) Bookkeepers who just handle tiny stores won't really become that much better, but if they sit there and fumble through thousands of piles of supplies they'll learn faster.
That's just how I think it should work, though. Getting better should be a challange, not an inevitable fate (Foregoing death, of course).
[ December 14, 2007: Message edited by: Dreamer ]