I think a lot of people would be happy to just see the 50 1.4 updated at the same or near same price.
Besides, a new 50 f2 will never be sharp at 1.4, but a 50 1.4 can be sharp at f2 
Just buy a 50/1.4 and stop it down to f2 or f2.2. 
The 50/1.4 is pretty darned sharp stopped down a little. It's already got good color, reasonable flare resistance, and the hybrid USM is fairly fast and accurate.
I ain't sayin' the EF 50/1.4 isn't due for an upgrade. It's an old, old design now and would be nice if it were sharper wide open. And I'd like to see improved reliability/durability with true ring type USM. It would give nicer background blur, too, if the 8-bladed aperture used curved blades.
Pretty sure we'll see something like the 24/2.8 IS USM, 35/2 IS USM, etc., in the next version of 50mm. In other words, I bet it will have IS! Eventually.... No telling when. It's been rumored for years that a new 50/1.4 was coming soon.
"....a 50/60mm f1.8ish with metal mount and ring-USM would be next on my list. At the moment I'm hunting down a 50mm F1.8 MkI as I don't like the mkII (plastic mount, heard enough horror stories about lenses getting stuck) and I don't like the 1.4 as the micro-USM seems slowish and appears vulnerable, the f1.2 is too Pricy for me and IMO not sharp enough for such a lens....."
Well, if you don't like the micro-USM of the 50/1.4, you're really going to dislike the micro motor of the 50/1.8, whatever version you get. The hybid micro-USM of the 50/1.4 gets a bad rap for its fragility... But few complain about it's focus speed, accuracy and consistency... which are considerably better the f1.8 lenses' AF system. (Folks who have tried to micro adjust the 50/1.8 generally give up... it's just not consistent enough to be able to fine tune focus.)
I have used the 50/1.4 for sports photography, and never had an issues with the focus speed. It's pretty comparable to 28/1.8 and 85/1.8 primes I often use along with it, both of which have "true" USM.
WIth some reasonable care, the 50/1.4 actually can hold up pretty well. Just get the matching lens hood and use it. When shooting, the hood protects the front barrel of the lens from bumps. When stored with the hood reversed, it protects the focus ring from bumps. Also "park" the lens at infinity when storing it, to retract the front barrel fully inside the outer barrel. All these are easy, practical things to do anyway.... so IMO no big deal... and seem to help the lens have better chance of a long, happy life. Also some folks think frequent Full Time Manual (FTM) of the 50/1.4 causes more rapid wear and tear on the focus mechanism.... I rarely manually focus mine. That and the fact it's always used with a hood might explain why mine is still working quite well 10+ years after I bought it (and it was used, so I really have no idea how old it is).
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Alan Myers
San Jose, Calif., USA
"Walk softly and carry a big lens."
GEAR: 5DII, 7D(x2), 50D(x3), some other cameras, various lenses & accessories
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