Funny that you posted this! I actually have been thinking about this as well. A while back I probably wrote a dozen different versions of these paragraphs, and this is where I’ve landed out.
TFA:
Luke Skywalker has vanished. In his absence, the radical FIRST ORDER has taken over the remnants of the Empire and will not rest until Skywalker, the last Jedi, has been destroyed.
Convinced that the First Order is secretly preparing for war, General Leia Organa mobilizes a covert Resistance to prove to the New Republic that diplomacy is not an option.
Believing that the Jedi are their key to victory, Leia has sent her best pilot to find her lost brother, Luke, before their dangerous new enemy reaches him first….
The First Order absorbing the other Imperial Remnants could be enough to rationalize their strength, basically that they consolidated resources to help build their new toys.
I think I’m trying to accomplish similar things as you are. “Radical” could be replaced with “mysterious” to further help explain the New Republic’s inaction.
TLJ:
The FIRST ORDER reigns. Having decimated all their leadership, Supreme Leader Snoke now deploys his merciless legions to seize military control of the fractured New Republic.
Only General Leia Organa’s band of RESISTANCE fighters can stand against this rising tyranny, certain that the hope Jedi Master Luke Skywalker inspires will reunite the galaxy.
But the Resistance has been exposed. As the First Order speeds toward their vulnerable base, the brave heroes mount a desperate escape….
Possibly switching around certain terms like “Republic”, “galaxy”, or add things like “allies”, “forces”, etc. might give you a better combo, but I tried to keep the crawls concise and to the point.
Two alternatives for the second paragraph:
Only General Leia Organa’s band of RESISTANCE fighters stand together against this rising tyranny, certain that the hope Jedi Master Luke Skywalker inspires can reunite their scattered allies.
Only General Leia Organa’s band of RESISTANCE fighters stand united against this rising tyranny, certain that Jedi Master Luke Skywalker’s return could restore hope to the galaxy.
I guess I am trying to emphasize the Republic as divided and the Resistance as united, and hope is what makes that difference, and Luke is what is needed to restore hope to the rest of the galaxy and reunite everyone. It should all tie back to the main objective, which is Luke. This idea extends to the TFA crawl. And I personally like the dichotomy of unity and power. When the First Order reunifies the Imperial remnants, they acquire the power needed to topple the Republic, which leaves the Republic in disarray and vulnerable. Now, the Resistance is desperate for the hope Luke inspires in order to reunite the Republic and the galaxy and give them the power they need to defeat the First Order.
I also like that you came around to “Chaos reigns”! Personally I think it fits better with the situation: the decimation of Republic leadership has left their remaining forces and allies in disarray, and that chaos is what allows the First Order to invade the galaxy successfully. Really, the First Order won’t reign until they have control of all the major systems, which Rey says will still take weeks to months.