I'm all for taking the high ground, but I highly doubt this will change the Chinese government's behavior. Google doesn't have such a huge market share in China and leaving will only help local competition (e.g. Baidu) that can be more easily controlled by the government. What leverage does Google have? This is really the classic engagement vs. isolation debate. The only thing that might have any leverage would be to…
Consider that Google owns about 65% of the search market worldwide (http://www.businessinsider.com/bing-who-google-worldwide-sea...). In addition, they enjoy a tremendous amount of goodwill - they are really seen as the good guys by a lot of people.
If Google wants to play tough, they have a lot to work with. At the very least, the Chinese regime would be launching a PR nuke on itself.