Wow! so its not just me then! Just had one as a hire car for a week in the Alps, 3800 km on it. I had the exact same feeling on the autobahn, thought it was weird side winds or something, but not a breath when I stopped.
Majorly gutless too, its just too big and heavily gadget laden for a low powered 1.2. Made my old 1.0 Polo seem rather spritely.
Those huge front pillars make it look bigger inside but act like horses blinkers on the twisties - awful! ...and they put little tiny windows in them (that the driver cannot see) as if that was going to help.
Gear ratios were awful in the mountains too, the gap between 2nd and 3rd was huge meaning I often had to sit screaming at redline in 2nd because I would quickly grind to a halt in 3rd even when it wasn't that steep.
The stupid shelf in the boot that denies you of 1/3 of the space so you have to take it out and put it on the floor. What's it for? to save grannies an extra 2 inch lifting of their one shopping bag?
The there's the giant, virtually 'touch sensitive' hazard light button that goes on every time you adjust the air vent just above.
Best thing about it was the automatic lights and even they were a bit slow to come on.
Don't touch one! The Fiesta is miles better as you said.
Z