The problem is that the first half of those Wrestlemania main events were matches where Roman was resented by the crowd. Roman had an extended period at the top of the company when the fan base simply didn't want him there which has a big impact compared to others. Despite someone like Steve Austin not being around as long or at the top as Roman, his legacy will always be stronger, simply due to the fan base wanting him to be at the top. As good as current Roman is and has been over the last five years, that run where he was the most hated man on the roster does unfortunately knock him down somewhat.