Don't get me wrong; I agree with your "good change" observation, and I wasn't saying the Twitter interface should have been frozen in time at 2006 (and I definitely wasn't saying there is no room for improvement, even now). I'm simply of the opinion that Twitter is rapidly losing sight of what their purpose is.
Twitter doesn't have a purpose, it serves a purpose.
We can all disagree about what function Twitter performs for individuals, or in the marketplace, or what have you. But it isn't like there's ever a destination for a company or medium or whatever it is that Twitter is.
I remember those days too and the product is much better now. It could be much better still.