Under 7 hours...
Ethernet - Static use at a desktop. Take your cable with you? A 3" extension on that cable is not much. Thunderbolt docking stations in the future..
If this is too much trouble; stick with your 2011 MBP.
FireWire - mainly used by A/V Pro's for integration into rack systems and devices. Small USB3 adapter to enable true 800mb/s I see as an upgrade if you want the newest MBP. How many updates to software do you see other than for compatibility? Quite sure your current systems are perfectly adequate if the use of an adapter to keep FW is too much.
ODD - the most controversial in my eyes but from experience in the commercial sector, cloud storage and even cloud computing is very easy to upgrade to for organisations (added option to currently used systems so not everyone can use it but in the next 18 months it will be available to most) if not available, I'm sure the current systems being are perfectly adequate to use. As for the prosumer - seriously what do you mostly use ODD for? Take advantage of disk imaging, cloud storage, thumb drives, external drive...
Shaving 1/3" off of an aluminium block would be a lot of weight to lose. The CPU will not dissipate as much at 22mm, same with GPU and Kepler pushing better graphics with the same if not less power in some cases. More room for battery, HDD-SSD combo and the use of near retina display via native support by HD 4000.
** Apple were supposedly using the A5X chip in the iPhone 4 shell for testing so no one notices - here's the supposed MBP version.
Steve Jobs set out his vision for at least the next 5 years (read Walter Isaacson's book) so his innovation is still relevant.