Well, reading this thread I am struck by the tone as much as by the replies. How the OP - or anyone chooses to spend their money is their affair. Personally, I think that the feeding frenzy surrounding the launch of a certain Timepiece With Extras is completely bonkers, but, again, each to their own.
Now, to the question asked: No, is the short answer, and 'it depends' is the slightly longer response.
As it happens, I have both. And I find both superb. Initially, I hadn't planned it that way.
In the summer of 2013, I was working abroad, and my 2010 MBA (which was 13") was in its third year of life, and third year of Applecare, hence it was time to buy a new one.
I ordered a CTO 13" MBA while I was home on leave - 8 GB RAM, 512 SSD, Core i7, and so on - but, because I was informed that it wouldn't be ready before I had to return to central Asia, - and my brother had been given my old MBA as a birthday present - I bought - as an emergency stop-gap - a 2012 11" with 256 SSD and 8 GB RAM.
I was amazed at how good and fast the 11" was; above all, I was amazed at how superbly and wonderfully utterly portable it was.
While the 13" was ready when I next returned on leave - a few months later - I was impressed by the 11". A colleague - spotting it - had offered to buy it as a gift for his ex-wife, - it was an amicable divorce - so I sold it to him when I next returned to work, bringing both computers with me.
However, subsequently, while I missed the stunning portability of the 11", I did notice a surprising difference in the screen size, and found that the 13' seemed considerably larger, and easier to work with over a long period of time. The only drawback of the 2012 11" (the one I sold) was the less than optimal battery life - but this has since been addressed in the 2013 and subsequent models.
Thus, last summer, I decided to order a second 11" - this time a CTO - built to the same spec as the 13". For travel (and I travel a lot), nothing touches it. Yet, for more 'heavy duty' writing, I prefer the 13" and use it - for now - as a desk top, although it is superbly functional also as a robust travelling laptop.
So, the upshot is I have both, and use both.
For now, the new 12" MB is an underpowered computer, with limited specifications, irrespective of the attractions of the retina screen, and, as such, it offers nothing worth looking at for me; it is a glorified iPad - designed for consumption of, rather than creation of, data, and, as such, it doesn't tempt me in the slightest. Over time, the specifications offered may well improve.
For anyone who commutes regularly, or travels regularly, one or other of the MBAs is undoubtedly the way to go.
Now, I will be honest and say that I don't expect this star of affairs to be indefinite. If I were to have a permanent base - which I haven't had for nearly a decade - I would contemplate a combination of - possibly a 15" MBP with a serious SSD drive, retina screen, massive RAM, etc, etc., plus possibly, an 11" MBA CTO. But, for now, I don''t need it, and in my current circumstances, wouldn't use it as it is far too heavy and large to lug around comfortably.
That is the thing with the MBA; either computer is a fast, powerful, and supremely portable - which is what is key when considering the MBA - machine.