I grew up in Hong Kong and still visit very often. In my opinion, there's little architectural significance in the old Central Star Ferry pier or clock tower.
But the protests are more than about the pier or the tower itself. It's a sign that some Hong Kongers have finally waken up to realize it's wrong for the government to just keep tearing down old things and filling up the harbor. Unfortuantely, it's too little too late.
I was reading a thread on a Hong Kong ferry forum, and I particularly like one piece. The author asked, where are all these people 10-12 years ago, when they took out all the other piers and filled the harbor to build the ifc? Lots of people used to rest, have lunch, whatever at the upper level of Blake's Pier and the garden next to it. Somehow, nobody even blinked an eye when those were gone.
[Personally, I spent a lot of times at Blake Pier, both on the upper level, and at the Discovery Bay ferry waiting area downstairs.]
So, it's really a lot more than just about the Star Ferry pier and clock tower.