I love the 50/1.4 on crop body (hardly use it on FF)... And my copy is very sharp at any distance from f2.2 and smaller apertures. Like most of them, it's a little soft wide open, but usable if needed.
The fastest zoom you can buy is f2.8. The point of having a lens capable of two stops larger aperture (f1.4) is not really for low light, that's sort of a secondary thing IMO... It's biggest benefit is it's ability to blur down backgrounds strongly. Great for portraiture.
I don't have 17-55 because I try to stick with lenses I can use on both my crop and FF cameras. Instead I use 24-70/2.8. I wouldn't want to be without some faster primes, though, to complement the zoom. They serve different purposes (I use 20/2.8, 28/1.8, 50/1.4, 85/1.8 and 135/2, in particular... might add 35/1.4, but that would be primarily for FF use).
So, no, I wouldn't give up the 50/1.4.
I don't know what's wrong with your lens. Maybe it's an issue Canon will repair, but I'd also look hard at technique. It's a reasonably fast focusing lens that's plenty sharp if stopped down a little. It's Achille's Heel is weak AF mechanism (and always using/storing the lens hood with it helps protect that... at least mine has been good for 10+ years use, maybe because it's always used with a hood).
An awful lot of "gear faults" have more to do with the user, than the gear. When you get your 50/1.4 back, do some more shots and hopefully it will be great. If it's not, post some shots here and show us what problems you are having, with EXIF intact and any relevant shot info you can provide. Maybe we can help.
Oh, and Canon seems to have addressed the dust and IS failure issues on the 17-55. We see far fewer complaints about these problems here on POTN, so I suspect Canon has made some mid-production changes to correct them.