The traditional LDS Sunday School version of Satan's proposed alteration to Heavenly Father's plan (henceforth referred to as Satan's plan for brevity) tends to be that Satan wanted to force us all to be good. This interpretation is not based in canonical scripture, and I believe actually contradicts scripture. There is an interpretation that (to me anyway) seems to bring everything into agreement -- both scripture and personal experience.
First let us review the basis for our understanding of Satan's plan. This quotation is from Moses 4:1,3-4 (emphasis added)
And I, the Lord God, spake unto Moses, saying: That Satan, whom thou hast commanded in the name of mine Only Begotten, is the same which was from the beginning, and he came before me, saying—Behold, here am I, send me, I will be thy son, and I will redeem all mankind, that one soul shall not be lost, and surely I will do it; wherefore give me thine honor.
Wherefore, because that Satan rebelled against me, and sought to destroy the agency of man, which I, the Lord God, had given him, and also, that I should give unto him mine own power; by the power of mine Only Begotten, I caused that he should be cast down;
And he became Satan, yea, even the devil, the father of all lies, to deceive and to blind men, and to lead them captive at his will, even as many as would not hearken unto my voice.
Not only does "Satan wanted to force us all to be good" not appear anywhere in scripture, it actually contradicts the above passage. Satan said "I will redeem all mankind." But if Satan was going to force us to be good, there would be no one to redeem because no one would have sinned.
For him to redeem all mankind, all mankind would have to sin. What is more, nothing would be required of us to be redeemed or else Satan could make no guarantee that every person would qualify. This is a deviation from Heavenly Father's plan, which required His children to individually accept the atonement of the Savior while we are here on this Earth. It seems then that Satan wanted to allow everyone to do anything we wanted and still be saved.
But the Lord explained that Satan sought to destroy the agency of man. Doesn't that mean he will take away our choices by forcing us to be good? Let me explain this with an analogy. Suppose you and I walked into a hat shop of red and blue hats. You were allowed to choose between a red and a blue hat, but regardless of your choice, you only got to walk out with a blue hat. No matter how many times you went back into the shop and asked for your choice of a red hat, you only walked out with a blue one. Did you really have a choice in this scenario? Sort of. Did you have agency? No. For agency to mean anything, you need freedom to choose and have those choices actually take effect. Satan sought to destroy the agency of man by ensuring that no matter what we chose on Earth, we would end up 'walking out' with Eternal life. Maybe, if the idea of doing anything you want and getting Eternal Life sounds a little more enticing than you first thought Satan's plan was, you can begin to understand why one third part of the host of heaven thought so too.
We are here on Earth because we understood the wisdom in Heavenly Father's plan and accepted it. We knew that some would choose evil, and for that we were sorry, but we knew that agency (our freedom to choose our own destiny) was too important to sacrifice.
One interesting fallout of this understanding of Satan's scheme is that Satan's scheme hasn't changed. Now that Satan is thrust out of heaven, he is lying to us by telling us that his own ideas are the correct ones. We see Satan's thoughts, for example, in some of the beliefs of Evangelical Christians, who believe they are saved regardless of what they choose to do... which was Satan's platform in the pre-Earth life. Frivolous lawsuits from plaintiffs who do not want to accept the consequences for their own stupid actions grow progressively more ridiculous -- another sign that Satan is convincing people that they should not be held responsible for what they choose.
Please help curb false doctrine by teaching straight out of Church publications (the ones with the Church logo prominently printed on the cover). Keep the doctrine pure. You won't hear me preaching my interpretation of Satan's plan in Sunday School until I can find a church publication to back it up -- but I won't be teaching that Satan wanted to force us all to be good either. Until I can find a publication directly addressing this, you can bet I'll be teaching about Satan and the war in heaven directly out of the scriptures to avoid throwing in any "extra bits" I may have picked up while growing up.