So, getting rid of almost 1 1/2 pounds of laptop with no give-up in screen quality or connectivity is really no issue at all. The slightly smaller screen might or might not be an issue under some conditions, since I often need to have two documents open at once and the 13.3" screen might be just enough bigger to make a difference - hard to tell without trying it in person.
The biggest issue is whether I feel like putting $1300 into that dedicated use (and keep the rMBP), or justify the $1300 by selling the rMBP (not inclined to do so - and I do things with the rMBP at home, like photo and video editing, that I'm not sure the rMB is a good candidate for. A secondary issue is whether it's dumb to buy a Gen1 design. The original Air and iPad were innovative but not fully developed (duh). Resale value is probably high enough that I might take that risk.