Thanks to all who provided their perspective. Just got back and am happy to report that we had a blast on our trip. We had a couple of days of what were reported as rough seas. I found that while you could definitely feel it (particularly in odd situations like taking a shower or walking) it wasn't the kind of pitching shown in any of the videos.
I recently had knee surgery and was a bit concerned about being able to balance in rough seas but had no problems whatsoever. We saw lots of folks with their little patches behind their ears but we all were fine without anything. After a while we just kind of would notice that "the ship is rocking" quite a bit but it was always more a comment made out of observation more than alarm. Any kind of rocking at night was great for sleeping and we just really enjoyed ourselves.
While we aren't nervous travelers by any stretch, I was a bit concerned more from a "how my knee would hold up" to motion side of things. What I came to realize was that there are people of all ages and abilities on these ships by the dozens. If you are unsteady the kind of motion I experienced didn't knock you around much - it isn't like turbulence on an airplane but more gradual in that it can cause what I would call more of a mis-step but that's about it. In any case, just wanted to allay any concerns like minded folks might have.
We enjoyed ourselves so much we booked another cruise on board. Yipee!