It's not a 'preferred' stock vs 'common' stock issue. The issue is that the CX free float of shares is around 25% of the total shares on issue. The other 75% are held within Swire and mainland chinese interests.
If we (cx employees) bought all the shares available on the market we would have 1/4 of the seats on the board. Not enough to effect change when the other 3/4 is answerable to Swire/Beijing and not the general public!