I haven't played Tsubaki's route yet, but Kannon's was pure garbage.
I'd have gladly traded a Mizuha route for a Yuki one -- but judging how much of an afterthought they seem to be it's probably not much of a loss.
I was hoping the Maou would have an evil team (like in a Kenshin manga or like in Monster) made up of especially powerful and disturbed killers, bu no, it's not going to be THAT great.