In my opinion, Senpai doesn't really need Dian given how strong Senpai's grid is already. Dian is useful for carrying WRags and helping weaker players clear stuff like GO but she just doesn't seem necessary if you have the stats to just kill everything before it kills you. Dian is also not that good for AABing since you actually have to use her potions.

On the other hand, Azazel AW is really fricking strong, and will be meta for a long time, so that's seems a better choice to me.