The low-speed "shuddering" is normal for any dual clutch transmission. The same effect can be felt on a GTI or R32 with VW's DSG transmission. A lot customers simply don't understand that a dual clutch transmission is basically an automated manual transmission, and that manual transmissions by nature have a very notchy feel to it.
Traditional automatics use a torque converter to help synchronize gear changes and make shifting smoother. It also unfortunately delays the process of shifting itself and saps power from the engine in the process. And CVT equipped cars don't have any physical gears to speak of, so they're even smoother. So any regular customer who goes from driving one of those to a dual clutch transmission car will probably think that something is wrong when they feel the transmission jerking.
Ford could definitely solve the problem by making the lower gears taller, or by inducing some type of artificial delay in the shifting process. However your fuel economy will suffer and the transmission won't feel nearly as responsive. Essentially you're taking away the two major benefits of even using this transmission technology to begin with.
The bottom line is if some people can't handle the way this transmission works, they should look into getting a car with a regular automatic or CVT instead. There's no reason Ford should have to resort to castrating the PowerShift transmission for the sake of smoothness. I'm sure in the future they'll find ways to make it shift smoother without compromising anything. But for now this is what it is.