Another thing that really annoys me! I had the steering rack replaced because of this exact problem on my previous 3.2 last February. Apparently the power steering is all in one unit so they replaced the lot.
It goes heavy light heavy light as you twirl the wheel at stationary or slow parking speeds as you say, as if the assistance keeps switching on and off.
Nobody else really seemed to have the same problem at the time (per this forum and certainly not the dealer, although they accepted the problem) so I just thought it was my car...again. ****** all good it did though. Even my new one does it, but it is only starting to be more noticeable - when I first got it, I thought they had modified something as I never had the problem. I have done just over 4k miles now.
Given the various A3s I have driven in the last 18 months, and the fact that all of them had this at one level or another, I would say that it is one of those "Audi characteristics" that can't be fixed unfortunately. Not ideal, but not for the want of trying to resolve it.
And Outlore, if you are out there, did you get your creaky steering fixed or have any news you can share as mine is continuing to get worse by the week? I must take it in!
Cheers