Mojowuq9
The Imperium and it's succeeding factions have been struggling uphill ever since the First Civil War decimated their nobility and military, which was comprised of vast reserves built up over time.
The Ascendant Dawn (one of the aforementioned successor factions) is primarily limited by a smaller fleet size than the Imperium of old, along with logistical problems when carrying out military operations in the Milky Way because the faction is located in a different galaxy.
The reborn Imperium has tons of issues left over from the Maw period, and pretty much every other mainstream faction hates them, and they just started a civil war with the Dawn.
That enough of a Cascading Weakness for you?