Those powers are may considered harmful due to their intent but remember Plo Koon found Elctric Judgment and he had not felt anger or hatred while using it and it had the strength of a blast i'd say of Dooku's. Whereas a variation Luke used referred to as Emerald lightning, instantly killed one of Shimrra's slayers.(sp?)
I wouldn't consider 'Force grip' to be a Dark Side power at all since technically It's only telekinesis it just depends what you do with it.
Force Rage, No I do not beleive that this power is inherently evil since people have used it without falling to the Dark Side, Jaden, Kyle and Kenobi in TPM. Though people like Anakin used this power passively and it helped his attack style (Djem So) the reason he didn't fall to the DS was because of his dread, i'll post the quote.
He lifted his blade, and beckoned.
Skywalker leapt from the balcony. Even as the boy hurtled downward, Dooku felt a new twist in the currents of the Force between them, and he finally understood.
He understood how Skywalker was getting stronger. Why he no longer spoke. How he had become a machine of battle. He understood why Sidious had been so interested in him for so long.
Skywalker was a natural.
There was a thermonuclear furnace where his heart should be, and it was burning through the firewalls of his Jedi training. He held the Force in the clench of a white-hot fist. He was half Sith already, and he didn't even know it.
This boy had the gift of fury.
And even now, he was holding himself back; even now, as he landed at Dooku's flank and rained blows upon the Sith Lord's defenses, even as he drove Dooku backward step after step, Dooku could feel how Skywalker kept his fury banked behind walls of will: walls that were hardened by some uncontrollable dread.
Dread, Dooku surmised, of himself. Of what might happen if he should ever allow that furnace he used for a heart to go supercritical.
Dooku slipped aside from an overhand chop and sprang backward. "I sense great fear in you. You are consumed by it. Hero With No Fear, indeed. You're a fraud, Skywalker. You are nothing but a posturing child."
He pointed his lightsaber at the young Jedi like an accusing finger. "Aren't you a little old to be afraid of the dark?"
Skywalker leapt for him again, and this time Dooku met the boy's charge easily. They stood nearly toe-to-toe, blades flashing faster than the eye could see, but Skywalker had lost his edge: a simple taunt was all that had been required to shift the focus of his attention from winning the fight to controlling his own emotions. The angrier he got, the more afraid he became, and the fear fed his anger in turn; like the proverbial Corellian multipede, now that he had started thinking about what he was doing, he could no longer walk.
I don't necessarily like a combination of Force Powers, I'll just stick with good ol' TK.
Edit- Longest post ever.