I hope this becomes a CR4 and then reality!!
The prime lenses listed in the CR1 for update are some of the lenses that I am looking forward to... particularly the 50mm f1.8
I have the 50mm f1.8 II, and love it's optical qualities (apart from the somewhat nervous bokeh at some settings) - howver I HATE it's AF: inaccurate, jumpy, and noisy. On my 350D the 50mm just 'didn't work' for focus critical applications and even on my 7D it is not consistent enough to be enjoyable.
So a 50mm f1.8 II upgrade (to a 50mm f1.8 III with USM would be a very desireable lens, if it is sharp & contrasty wide open, good bokeh and accurate AF. Build quality similar to some other prosumer lenses I own (eg Canon's 15-85mm, Canon 100mm f2.8 macro non L) or even my Canon 28-135mm would be great.
Hope I can say this on this forum without receiving virtual stares / glares
but I'm actually jealous of one of my friend's Nikon 35mm f1.8 It's a very versatile lens & he's used it to take lots of good low light shots... So an upgrade to Canon's 35mm f2 (either at f2 or f1.
would please a lot of Canon shooters like me too.
The current 85mm f1.8 has received a lot of praise due to it's USM, decent build quality & high optical performance (though it has noticeable LoCA...) However this isn't always field critical for every application. Personally, this lens isn't on my wish list. But I can understand others for whom an update & improvement to that lens would be a real winner.
Now... just putting it out there.... I wonder if any of these prosumer primes (35mm, 50mm or 85mm) would get IS? Now that
would be impressive. Without IS I'd be prepared to pay around $500 - $600 for say the 50mm f1.8 if it was a good performer optically / decent build quality (though prices would probably come down in time). With IS, I'd be prepared to pay a few hundred dollars more.