The only downside to the rock wall is that availability is limited. I expected the wall to be open every day, all day. It's not. You have to plan your schedule around it, if you want to climb, and that seems to be a foolish way to market this attraction. I mean, am I going to jerry-rig my excursion schedule just so I'm back on the ship during the 60 minutes (or whatever) that the wall is open? I think not. Same with the rollerblading rink. It's not open for very long. Nor is the golf simulator.
They go to all the trouble and expense of putting these attractions on the ships (I speak only of the Navigator of the Seas, having just finished a cruise on May 3), but then they limit their availability by only being open for certain hours of the day, and not very many of them, to boot.
If they have dining room people tending the dining rooms all day long (Windjammer, Cafe Promenade) and if they have stateroom attendants working all day long, why not have the rock wall, the inline track, and the golf simulator working all day long, and into the night in the case of the simulator? That was a surprise, and a disappointment - that those attractions weren't available more.