A Super Junior Conspiracy Theory: Ryeowook the Visual Singer

Yes. Indeed. Long title aside, my cousin recently told me that there are usually the same five Super Junior guys featured on posters and albums. Three of them, she said, were the primary three. They were Siwon (Obviously), Donghae (Okay, very reasonable), and Ryeowook (Huh, what?). 
We decided to test it out and it was true! Gasp. Now the only real question was why. Siwon and Donghae both have great muscle definition and good faces. They make sense. But Ryeowook? He has the persona of an innocent young lad, and he's so petite. That's not something people are normally drawn to. Why would he be featured over someone more typically handsome like Leetuek or Sungmin?
At first we questioned if it was to balance out the two more bulky guys (Siwon and Donghae). Then we wondered if it's because he's a top 3 best singer in Super Junior. Neither of those made satisfactory answers. There's other guys who could provide balance, and why not feature the other two good singers; Kyuhyun and Yesung?
Finally, I was led to a conclusion. The only reasonable answer to the riddle was, clearly, that Ryeowook, circled in pink above, is a visual singer. People mostly like him because they think he's hot.

 ...Or not. He actually has a great voice (always recognizable, except when listening to SS501 in a mixed playlist.) and is one of the few counter tenors in Kpop. While his featuredness remains a mystery, there is one conclusion that can be made. Siwon, Donghae, and Ryeowook are not actually featured as much as my cousin and I were first led to believe. As I was looking up cover art for this blog, I found lots of pictures which featured the other guys...especially in the Japanese versions, or when Kibum and Hankyung were still around (Yeah. Go Your Royal Hotness 2009). Therefore, they are not actually featured all the time. The camera love is shared.  

In the picture above Ryeowook is circled in pink, Donghae is circled in black, and Siwon is circled in green. Sorry that some of the circles are super hard to see, especially since the picture is to illustrate how often they appear on cover art.
Picture credits to