Having destroyed my MBA I faced the same decision. But as much as I loved its size and shape, I have to agree that the two being so close in price that the retina display is impossible to turn down.
I had the same configuration for my MBA, and found 128GB storage to quickly become a problem. Remember you lose 8GB as an image file is needed to store the memory when it goes to sleep unless you reconfigure system settings. And eventually it will start using swap space or creating temporary files so the available disk space starts to go down the longer you use it between reboots.
It also means you cannot use Bootcamp as there is not really enough space for a working Windows partition. This may not be important, but depending on what games you play it may be something you would want to use.
Something I read afterwards that never occurred to me at the time of purchase is that with the speed of SSDs the swap performance is so much better than traditional hard disk that in the same situation now I would seriously consider 256GB storage and 4GB of RAM rather than a 128GB and 8GB configuration. Although I believe it is fairly easy to get a third-party upgrade to your storage but not the RAM so that is a decision you need to get correct at time of purchase.
But having previously used MacBooks (and PowerBooks) with optical drives and not having any problem with the weight, the rMBP now being only a half pound extra over the MBA seems a minor quibble unless you need to carry it in an already heavy bag. Size is overall not too dissimilar, the tapered design of the MBA is much better, but at its thickest point you are not saving anything. And while the MBA battery life may be better, unless you are someone wanting to work on long haul flights again it seems a minor quibble when the rMBP battery is still great.
In reviews I have seen the MBA i7 buts is roughly on a par with the rMBP i5, with the latter benefitting in processor intensive tasks as the boost on the MBA cannot be sustained for as long as it cannot dissipate the resulting extra heat as well. The rMBP also has a better graphics processor and I believe, though not certain, the flash storage is faster. Although I may be confused by Apple referring to the rMBP as having the faster "PCIe-base flash storage" while the MBA as just having "flash storage." If you want the machine to last four years, then the rMBP being faster and with better graphics and screen means it should cope better as software becomes more demanding.
I would be happy to trade the performance of the rMBP for a retina MBA as they are wonderful machines. But sadly that is not yet an option. Given your are not concerned with the weight and battery benefits of the MBA, which along with the ergonomics are the only reason to favour it, but do want the "less obsolete in four years" benefit of the rMBP it seems the latter seems easily the best option for you. And if you want to store an iTunes library on it, work with RAW files stored locally, or just install a few big games then the added storage space will be a huge difference. It is scary how quickly you can use up 128GB, iPhoto uses up more than 1.28GB for the application alone.
