So, after all that, my question is this. As I'm not shooting moving targets where the 1.4 will buy me a usefully faster shutter speed, wouldn't I rather use the new 28 @ 2.8 with its four stops of IS at a higher overall IQ than the 35L wide open? In my unique need, isn't the new 28 a better choice?
I have one more comment for you, since you're a lensrentals.com blog reader. The new 24 and 28 IS lenses have been a conundrum to me (and many others) - they seemed overpriced for f/2.8 primes. For the longest time I struggled to think of why someone would want to buy those lenses at their offered prices.
Then, Roger at lensrentals figured it out for us. On your new 5D3, the 28/1.8 IS USM is one of a handful of new "super focuser" lenses (my term, not his) that has a rotation detector, and is thus able to fully realize the advanced AF capabilities in the 5D3 and 1DX.
The current 35L, being a dated design, is not in this category. Its long-rumored successor almost certainly will be, if/when we see it.
Personally, I have an ancient 5D classic, so I will pass on the new 24 and 28 (plus I have a 28/1.8 I'm pretty happy with). But if I were in your shoes, I would seriously consider it unless I you feel like waiting for the new 35L (which could be a year off and $2000 and huge).
Here's the blog:http://www.lensrentals.com/blog/2012/08/autofocus-reality-part-3b-canon-cameras
BTW, love your spreadsheet!