I agree with this. Maybe with demons in control, the angels could not do anything. But with Mundus out of the way, maybe they have a plan of their own for humans?
Think like what Bob Barbas said: Humans were full of sin and corrupt and should be told what to do. What if angels think that humans are sinful creatures who need to be controled?
The only angel we know a bit about is Eva. She fell for a demon. As there is a war with demons and angels, I don't think angels would be too happy for Eva to be with a devil; maybe even thought Dante and Vergil were abominations and unclean because of demon blood. Plus, we don't see any angels come to help when Mundus attacks Eva.