Red Lightning absolutely has to stay. Not only does it work aesthetically, but it shows that Palpatine is at his strongest and “all the Sith”.
But, respectfully, I’m kind of arguing that “I’m even MORE strong” doesn’t really up the stakes. Just like “Starkiller base is even BIGGER than the Death Star” didn’t either. It didn’t add any emotional value for us.
What’s the more emotionally powerful moment- the massive fleet of strangers showing up at the end of TROS or Han returning to shoot Vader away followed by Luke’s one-in-a-million shot? One’s bigger, one features two great character beats that wins the day.
A starship that can destroy whole solar systems is not more exciting than one that can blow up planets, and a monster who can lightning a fleet isn’t more exciting than a monster who can lightning a person.
Emotional stakes come from relevance to the characters we care about, not from power levels. The relevance of this scene is Rey’s conflict with the temptation of darkness, and her need to protect her friends.
I’d propose that “I am all the sith” be removed instead, because it’s emotionally meaningless to add a new complexity to sith lore at this point that doesn’t add any value beyond power levels. It feels like an attempt to set up Rey’s “I am Iron Man” moment, which doesn’t need to be spoken when using jonh’s wonderful Jedi spirits shots.
The things that WOULD add value are anything which helps explain Palpatine’s return beyond “unnatural somehows”, for example putting Palps in the tanks instead of Snokes, and for my mileage, hints of unfamiliar magics (preferring green for the Nightsister angle).