It didn't replace Utaban, it's on way later than Utaban was. It's also sent live, starting at 11:50PM. Which is why groups like C-ute/Berryz/MM can't perform on it as they have underage members in their groups.
But it is a Nakai show, which automatically makes it very popular and having just
any H!P member on will be awesome.
Hell. Watching her message on the site, it appears she'll perform and such as well. Awesome.
Seeing that SKE will be on there makes me curious as to how they will do with their members though.
As any of them under 18 can't work past 10pm.