I've used mine mobile and desktop bound since I got it in November 2008, (13" MacBook) and it has served me very well, only getting a new Mac this month. I use a Rain Design mStand and plug in my 2 external HDDs, 23" monitor, speakers, Apple keyboard/trackpad, and whatever USB devices I'm using and primarily use it for web, iTunes, lots of Aperture (on 4TB drive), Adobe CS5 suite, Office, Parallels VM (Win 7 and 8) and more.
Seeing as all this was on and old Core 2 Duo MacBook with a 9400m, the newer models are like butter. And I had no issues with my old one other than the aging GPU running 1080p screens + internal on 256MB of shared RAM.
The henge dock is a great solution, and it makes it easy to keep a fast USB 3 or Thunderbolt drive and monitor at the desk, while still allowing you to go portable quickly and easily. Easily a desktop replacement.
Not sure what more oomph your rMBP would need, other than the HD4000 isn't that great at retina resolutions, but using an external monitor it should be perfectly acceptable, if a 6 year old card I was using was pushing apps fine, this should be great. Aperture is pretty much laggy no matter what mac you're using I've found. Our 2007 iMac has it and my new rMBP doesn't run a whole heck of a lot different than the iMac. It's just the way it's coded unfortunately. We'll see how Photos goes.