I upgraded from a early 2011 and went for the new one.
Processing power is very suitable witg the 2.7 for big projects, it will definetly handle everything in like every studio ive seen where you don't have dedicated workstations.
I think USB-C is future proof, i like the possibility to travel with a 29w charger and i need anywas - just like you - a hub when i the studio, with both devices.
The situation for small usb-c "docks"/multiport adapters is very nice, and it's a very fresh market.
So maybe go for a multiport adapter with displayport, passthrough charging, a few usb-ports and hook a 60w charger on it and you will be fine.
when not running 30 channels with plugins all the time you can go for a 29w- at least without draining the battery.
I do this mostly, not a quick one but i charges over the day.
hope there will come powerful, small chargers (got the ugreen 29w forfrom 16€ amazon) in the near future.
wanted a cheap one for the time until usb pd settles.
The apple charger is at home, for a quick charge every time i'm out of power.
For the interface i would use a direct cable, or dongles, if you got a fw-exclusive one. Just hold the number of plugs between the card and your macbook to a minimum.
IMO design and keyboard / trackpad are much nicer and you definetly will be lucky about every gram if you travel a lot with it.
Touchbar is nice but useless at this point for audio work.
I see some potential though.
I really like the 2016 machine and would definetly go for it again, especially for worklows where you need more ports than you got anyways.
Edit: if you're producing music on a reasonable way (not having 100 plugins or 30 channels active all the time) you should have more than enough power.
And there souldnt be a big difference in performance on these both.