I've got the same feeling. Wouldn't mind having another '12 quad i7 as spare. Because I don't want a down featured '14 one, and my gut feeling is that the next revision will be like a fat Apple TV, without any user accessible or replaceable parts. No upgrades. No fixes. Just toss it.
The only thing I see against it is getting 4k display.
Well, that and the vibes I get from Apple's UI choices, in both mobile and desktop. Time again to start looking around for alternatives in hardware and software.