Now you said that Asada was dominant (or co-dominant at the least) for four or five years, while Arakawa was virtual no-body until her peak late in her career. I wonder how you made it 5 years given she was ineligible for senior International Championships. Let's see how Asada really fared during major competitions (I'm just using official statistics of placement, not taking any POV about the appropriateness of placement into account). For the brevity, I will restrict it to International Championships and Grand Prix Final.
2005/2006 (Half-Junior, Half-Senior): 1st GPF, 2nd Junior Worlds
2006/2007: 2nd Worlds, 2nd GPF
2007/2008: 1st Worlds, 2nd GPF, 1st 4CC
2008/2009: 4th Worlds, 1st GPF, 3rd 4CC
2009/2010: 2nd Olympics, 1st Worlds, N/A GPF (failed to qualify, 9th in ranking), 1st 4CC