Saying a HDMI is too big for the slim MBP is a little exagerated. A HDMI port is about the same size as a USB port. Idealy the best case scenario is if Apple came with a Mini port that included digital sound out and from there, you could use a Mini port to HDMI and actually get sound (Not adding another physical port to the MBP and maintaining sales of their mini adapters)
Some things that would definitely improve the MBP is a esata port, HDMI, BD, and USB3.0"when available. <- This one could replace the FW800.
I currently have a macbook and am using optical & HDMI but I can definitely agree that it's very inconvenient. If and when MBP comes out with at least HDMI (In any ways) and BD, this would definitely makes me consider buying a new macbook, esata would be a nice addition. USB 3.0 I'm sure mac will add those once it comes out.
Like someone said, why have an extra input (esata) when you rarely do mass data transfer and waiting is no big deal... Well isn't it what technology is all about, making things faster, better?
I for sure don't like having to constantly connect a DVI & digital sound everytime I like to watch a video on my big screen.