I'm happy I got my 3ds and the Circle Pad Pro, just wish they would make a true "upgrade" instead of now with this new XL making game developers choose to ignore making usable CPP optional controls...
I am going to go out on a limb and guess Nintendo's thoughts making the DS were probably centered on the stylus reducing budget/effort towards a second analog stick. Win or lose Nintendo makes kooky hardware things it's what they do.
...but yeah dual analog sticks have pretty much been the standard since the Playstation and it is kind of dumb not to have them from the get go on the DS. Although the Playstation did not originally have them which does kind of make it a successful hardware addition. Then again it was added standard to the Playstation system package making it less of an addition and more of a revision. Rambles on...