The point i'm trying to make is a small powerful laptop does all of that. Yes you compromise the screen space while travelling but you dock the device when at home to a much bigger screen. For me the 15" inch is a compromise, it's bulkier than the 13" but the screen isn't big enough to do anything you couldn't do on a 13", you'd still have to connect the 15" upto an external monitor so you're just lugging a bigger laptop around for no reason.
Xcode is pretty much unusable on the 13" MBP. You can have one of the side columns open but not both. Its perfectly fine on the 15" model though.

. It actually still looks great at 900p or 1050p though, not retina but as good as a normal tft at native but to each there own, I personally love having the choice (And I would never run a normal tft non native).