Removing the ".@" syntax is a mistake. I don't always want to broadcast replies. I still don't understand why URLs are still included within the 140 char limit either. Can someone explain that better than the article?
I've been working with people helping social media for a bit, and one common issue in preparing a list of tweets to schedule is making sure the length is ok. So you end up with silly xls files where you have a url column, a text column, etc. and weird formulas to compute the size.
I think Twitter just wants to simplify the life. You can send 140 chars of text/comment. Mentions, urls, images, etc. are not counted because normal people aren't counting like that.