That's completely bizarre and makes me wonder if any other sentai shows had cast switcheroos. Tsuchiya...coming off of people like classics like Daisuke Shima, Toshiya Fujii and Kotaro Tanaka just doesn't seem very Reddish (his twin, maybe, who has more of a dark streak). But I could see why they would cast Wada as Kazu, who looks like more he'd be more of like Shou/Change Griffen type in that he was actually more of a cool womanizer and not just a weirdo hairdresser like Kyousuke/Battle France.
I've heard of other co-stars auditioning for the parts (imagine Yutaka Hirose as Red Flash!), but I find this to be pretty strange and neat to see that they actually was putting together a publicity package and already had the parts cast that way.