The Force Storm is not ritualistic in nature, Nebaris. It doesn't take six zillion minutes to prepare, and Sidious doesn't sacrifice a goat to create one nor does he light a bunch of candles and start singing a Gregorian chant.
Here's the explanation given in the Book of Anger:
The Book Of Anger
"Emperor Palpatine's first volume deals with the use of emotion to control the Force. He considers anger to be the most potent emotional form. With anger, the Sith can call upon the dark side, harnessing it for great power and destruction. Palpatine teaches that anger and rage, mixed with intelligent control, call upon the dark side with a very fine level of control, and can even kill from a great distance.
An excerpt, on the creation of Force Storms:
I have learned that Anger and Will, joined together, are the greatest power.
I have learned to meditate upon Anger and Will with clarity and precision, and I have learned to open the hidden reservoirs of dark side power.
Anger concentrated by Will in the vital center of the body creates a portal through which vast energies are released -- the energies of the dark side of the Force.
Standing watch with the mind, in my meditation of Anger, I have slain my enemies from great distances, through the dark side power that permeates the galaxy. I have created lightning, and unleashed its destructive fire.
Using this knowledge, I can unleash the dark side energies that are all around us, even to shatter the fabric of space itself. In this way, I have created storms."
Seems pretty ritualistic to me.
Sidious's Force Storm speaks of the level of destruction that he can create;
It speaks for his willpower and the depth of his anger. That's it. Read above.
regardless if it is based on sheer power, it is the most devastatingly powerful Force assault we've seen.
The sith ritual that Bane was performing was more powerful, I'd say, though he did require the power of about 20 other sith lords. I'd also say that Nihilus draining an entire race of force sensitives as well as about 100 jedi is a more powerful display. And that's just destructive power, in terms of general power, I'd also say there are a few others, such as the Black Whole feat produced by Luke and Kyp.
Luke has not been shown distributing such power on another Force user, and while I'm not doubting his power rivals Sidious's, Sidious's techniques, experience, and offensive lexicon outmatches Luke's own.
Wow, Sidious has a greater knowledge of force techniques, so what? Since when does having more make any difference whatsoever, when you have as much as Luke already has?
It's more plausible that Sidious will launch a Force Storm at Luke and get away with it than Luke using a blackhole.
Either scenario would never happen, but if you're trying to act as if I was saying that Luke will just use a black whole against Sidious, then you need to go over and read through what I said again; all I'm saying is that Luke achieving such a feat is great testament to his strength with the force, and can be applied through other means (force push for instance). The same can't be said about the force storm.