People have returned season after season to Kings Island with far less incentive as far as "new attractions," and they'll continue to do so next year.
Instead of considering 2012's new Soak City and wave pool to be a huge attraction addition year (comparing to 2007, 2009, etc) consider it an infrastructure year that just so happens to include a medium-sized addition (2010, 2011, etc). Very few of us would argue that the water park was fine the way it was and that it could sustain another five or six years with its then-current offerings. In fact, many people here said that the water park needed major updating and upgrading.
So just like last year, when we saw many, many small improvements throughout the park and a few medium expenditure attractions (WindSeeker and Dinosaurs Alive), this is yet another year of much-needed small scale updates and refurbishments with a fair sized attraction thrown in for marketing purposes.
There's nothing wrong with years like 2011 or 2012. Remember that for a very long time, that's how Viacom ran the parks. A handful of parks got clones of the same medium-sized ride or received their own medium-sized attraction with general park improvements thrown in. Years like that allow every park to get something new (which every park is next year, as far as I've seen) as opposed to two or three parks getting huge coasters while the other parks receive virtually nothing and sit stagnant, waiting for their "turn." Many people here were absolutely enamored with last year's way of doing this. We enjoyed the repainting, the attention-to-detail, the ride soundtracks, the returning effects, the small details that indicate at least an interest in maintaining the train and Backlot and the Crypt... 2012 looks to be shaping up similarly. No $25 million addition, maybe, but a refreshed, revitalized change or two with a nice attraction that was needed.