The situation is a little different here. Previously they dropped Firewire 800 and had only a Firewire 400 port, which pissed people off because Firewire 800 is faster.
Now, they dropped FW400 and have a FW800 port. This is a complete non-issue. Firewire 800 is 100% backwards-compatible with Firewire 400 - it's the same six pins, plus three more.
Plus, even the models with two Firewire ports still had only a single Firewire bus, with (basically) an internal hub driving the two ports. You will not see a difference in speed between the new MBP with an external hub, and the old MBP's with their internal hub.
Finally - if you look inside the case, there is physically just no more room for any more ports. The CD-drive and hard drive take up all the space on the right side, and the battery and existing ports take up all the space on the left.
I don't know what the story is with the MacBooks - maybe there wasn't any room in those either. That decision seems braindead to me (should have canned Ethernet instead - it's a laptop, after all), but dropping FW400 from the MBP's wasn't.