In my experience, White Dwarf Flare is Knockdown and not Knockback. Or, to put it technically, it's a <1 mag Knockback.
The Human and Nova forms are higher mag knockbacks though. And I do agree that, at least, the human form melee/ PBAoE attacks with Knockback should be <1 mag. With the possible exception of Dawn Strike, for thematic reasons. Seeing as they are counter productive for the PB.
Although, I've been able to beneficially reposition enemies with the KB from those (human form melee and PBAoE) powers on occasion. But, that is an instance that is not very common in most combats on a team.
I do not, however, think the Nova form KB powers need their KB mag reduced to <1.
basically, if it's ranged, keep it as is, if it's Melee, make it KD. that is about the only change I see that is reasonable and thematic.