Recommend waiting or buying something else than mac. Maybe if people stopped handing over way to much money for glitter covered turds, apple would release something good again.
Really, is that what you think? What pray tell are you needing an rMBP or iMac to do that the current iteration, or frankly many from the past 3 years can't do for you? Sure, there may indeed be a few things where bleeding edge power (cpu or gpu) may be of benefit, but there are millions of people who earn a living using their current and older Apple computers.
To me, it seems like you're just taking a page out of the tired old PC market playbook, where they need to constantly update to pitch the latest and greatest (even if it's not actually great) hardware specs, because people think that gaining that extra ~13% of speed or power or whatever will transform your ability to get work done.
Even when I read some of the reviews of the latest and greatest PC hardware - the ones that are chasing after Apple's thin and light design, they often end up admitting that they're trading off things, like battery life, heat generated, or smoothness and responsiveness of trackpad, while pricing (for truly comparable product) does not show the Apple tax, but rather that there is now a PC tax in order to get to similarly equipped product.