MBP has the right amount of ports and capabilities for most professionals. What exactly are you referring about?The pro machines are already plenty thin, nobody is asking to make them thinner. As someone else said, beef them up as PRO machines, add more ports, upgrade options, and capabilities that Pros can use. The thin MacBook is already accomplished with the Air.
In terms of upgrade options, I think those days are over in terms of Integrated Silicon on Chip design of the AS. However ssd upgradability could be a great thing.