No other property is even close to as big as TWD for Universal to do this type of thing with any other property. It's the biggest crowd drawing IP the event could possibly see for years to come.
This is kind of my point. 2014 (or 2015) won't just be "the next Walking Dead," because there won't be another Walking Dead for years, possibly decades. This year, if there was no TWD, none of the other IPs being used are big enough to be the "face" of the event. A CitW house may bring out some die-hard horror fans, but it doesn't have the same pull to the general public that TWD does.
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It wouldn't bother me if it didn't absolutely suck last year.
I thought it was better than Silent Hill and the awful Penn & Teller, but didn't amount to more than a mediocre house by any stretch (3-hour lines not withstanding). I hate-watch the show, and if there's a glimmer of hope, it's that Season 3 had a lot more iconic images than Seasons 1 and 2, which really just had the hospital doors from the opening scene.
But even if it's bad, the general public loves it--a house and set SZs will eat up non-fanboi crowds.