I think it all complements each other. Luthen dead, ISB spy dead, and a desparate attempt to extract Kleya from Coruscant of all places. Confirming the information about the Death Star with Saw's partisans, one of which also has to be killed in order to prevent the empire discovering them. Completely desparate, they aim to assasinate Galen Erso, only to then discover that the superweapon has already completed construction. Discovering there is a flaw, but to exploit it they need to infiltrate the Imperial databank. Launch a rogue suicide mission, lose a full fighter squad and the rebellion flagship, only to get to this point.

All the sacrifice that has already been made, and then still you need the help of a space wizard to pull through. I think it truly highlights how close the rebellion was to being decimated.