I stayed in an aft mini-suite on the Ocean Princess last Jan. I have also stayed on a mini-suite midships. There is definitely more movement in the aft than there was midships. There seemed to be more of a shifting from side to side movement rather than the rolling movement I encountered midships. However, I did not find this to be overbearing. You are on a ship and some movement is to be expected.
I found this to be so distressing (tongue in cheek) I booked a suite (right next door) for my March 30th Ocean Princess adventure. What suite do you have booked? I'm in C749. My in-laws stayed in suite C746 on the Jan cruise. You won't believe the size of the balconies. In addition the suites are wonderful. If you happen to follow me in the same suite, you will be able to see the scratch marks on the carpeting where they dragged me out kicking, screaming, crying and grabbing on anything I could get my hands on. If there is a delay on getting into your cabin, relax they are still trying to offload me. I'm a big boy and I figure it will take about 8 or 9 of them working in shifts to get me out. Last time they had to get the tranquilizer gun out and I heard them muttering something about an elephant load. Still trying to figure that one out. You are going to have a great time.
PS. Don't worry about the wet carpets, I promise it will just be my wife's and my tears from having to leave this wonderful ship.