Hi Marek, Yes I have the exact same issue... the rear control dial presses too easily when I'm trying to rotate it with my thumb. I had my camera repaired for another issue (via SquareTrade warranty service) and also told them about about the rear control dial.
When the camera was returned it was obvious they'd fixed everything *except* that. For now I try to work around the issue by pressing downward on the dial as I rotate it, in order to gain a bit of traction with my thumb. Also, the dial functions a bit worse, even, in cold weather.
Randy