I'd say it would be a pleasant surprise if Canon decided to make a 35mm f/1.2, but like others have mentioned, the size and price wouldn't be such a pleasure. For updating the current 35L, I'd say it's about time even if there is nothing wrong with the old one. I'm sure there are benefits to newer coating and manufacturing processes and there's always something to implement into an old design.
Then to the discussion about 50mm lenses. I've been wondering that if the 50mm focal length is such an easy thing to design, why on earth there isn't a decent one for Canon cameras. There are good ones with no AF, but all AF lenses are something I don't want to buy.
Nifty fifty is just a toy and the 1.4 isn't much better. The price/performance ratio might be tolerable, but price-wise it's just where it should be, maybe a bit too high. The 50L doesn't seem to impress with its sharpness so that's another candidate for an update. Sigma took the 50mm 1.4 in the right direction with added aperture blades and sharpness, but once again screwed up the AF. Inconsistent and slow, so there's really not a lot of choices if you want a good 50mm lens.
You can tell I'm in the market for a 50mm lens for my kit, but everywhere I look I see rotten fruits...