TB can be convenient for a one cable docking solution, where all your peripherals are connected to a TB dock, and there is one cable connected to the rMBP. When you want to go mobile, disconnect one cable and go.
Thanks a lot for mentioning this. I considered buying a MBP and was totally turned off by the fact, that it only had 2 USB ports. I need 2 of them permanently (mouse, internet stick) and a third one for external HD, Backup/printer/USB stick (basically a port for "random use"), so it would be a pain to work if I had only 2 of them.
I wondered where all the people plug in their external hardware and - bum - there you say it: the "Thunderbolt Dock". I didn't know such a one existed until I read your post. I thought I'd have to buy a common USB dock. But then I saw your comment about "1" connection with the TB and read up on it: unbelievable, but ALL PLUGS MISSING IN THE MBP EXIST ON THE THUNDERBOLT DOCK, which is Ethernet, Microphone, USB, etc. And you can connect it to the Macbook altogether by 1 single wire. All of them! Great!
Now this is kinda awesome, because it's a convenient all-in-one solution - but also kinda sad: it basically forces me to additionally buy a thunderbolt dock when I decide to be a MBP user. I am bit conservative in these regards: I keep looking back to the MPB 17" and even consider buying a refurbished one (however can't find them anymore) because of the simple fact, that it had DVD, Ethernet, 3 USB... all in one - and now: now you are forcefully pushed towards becoming a different user: a user that needs to buy a TB dock station to be complete. A user who has a whole lot of cables on his tables (which is ugly, regardless of the colors: silver, black, white cables, all hanging around and stuffed on your desk. I hate it on the former clean desk

).
If you are like me and changing your workplace location multiple times per year, you are likely to be annoyed by the fact, that you should buy an additional box to get your productivity done, as well as dragging the additional box with you every time time. It's like Apple only wants us to do "web surfing" while the MBP is undocked. Ridiculous. I bet - if they could - they would give us only a tablet or a MacBook Air and ditch the whole Macbook Pro series because: "these small screens are not up to the task for productive working anyways - so we just assume they connect these to an external screen at the specific working place. No need for 13" or 15" anymore either."