QUESTION - What would be the Plot for Your own "THE THING" Movie ?

Mine would be more on the lines of better Science. The way it's been explained so far hasn't made any sense as to what the Thing is.

As explained thus far, there's no way to beat the Thing. It should have already taken over the Universe.

Therefore, it's already taken over. It controls every bit of the Ecology.

So why does it consume organisms? Not for food. Not for Energy. The "duplication" has yet to be explained as to what the net outcome is on the organism's cognition. Is the Thing dominating every thought actively? If so, then the duplication of cells doesn't make sense. Is there a nerve center inside the brain which is the Thing's sensor for the "queen" thing.

Macready and Childs are too dull both for a sequel, and to believe they survived. The girl in the other Thing would be more credible as a survivor, even under her circumstances. You're not going to beat the Thing with muscles, obviously. 

In fact, you can't beat the Thing. It's an oxymoron that the Thing even believes there's a fight against it.

So, my sequel would deal with the Thing invading the world. Little pockets of people find they are unsure of who is a Thing sensor, and who isn't. They eventually come to realize the Thing doesn't consumer for ATP, but instead for "knowledge", which is the only reason why the Thing doesn't just consume every organism there is, and germinate cells in a lab for ATP, the logical and inevitable conclusion to a thing using organisms for food.

That explains the pick and choose mentality of the Thing. If it consumes all of a young girl's classmates and all her siblings, it has all the information in the nerve center that she offers. Consuming her would be like consuming a donut hole, even worse. Complete indigestion. What little knowledge she has would be just a few personal trinkets that the Thing would find worse than annoying. 

Each pocket of people slowly come to this conclusion. I would focus on one group of relatives in middle America in which the leaders making the decisions are the ones already ingested, and probably no one even gets killed on screen. I'd have them in a room where one character we'll call "Mr. Cool", who is not infested, and who has nothing to speak of, sees one of his relatives change from the Thing to his cousin. He then engages in the conversation with the Thing that had been eluding them all. 

We find that Mr. Cool realizes the Thing just consumes for information, and that people will just have to learn to live with the Thing. The Thing actually believes he is Mr. Cool's cousin, but is really at the mercy every second of the Thing taking him over. Since the one not infested has no weapons, he knows that the Thing could have taken himself at any time, and he's insulted that he wasn't invited to become part of the Thing. Two other relatives come in, hand Mr. Cool a flame thrower and tell him to burn the cousin. Mr. Cool says that would be like snipping an unwanted fingernail from the Thing. The two relatives smile and confess they are part of the Thing, and he is correct, but he lives in their Universe now, and they rule. The cousin begs to be burned. Mr. Cool won't do it, so the two cousins do it, and call into Mr. Cool's boss to register a complaint against Mr. Cool. They tell him to shape up or he'll be unemployed. They leave Mr. Cool with his cat, and the film ends with Mr. Cool wondering if his cat is a thing, then deciding it doesn't matter. He goes into work just as if nothing happened, and so it occurs all over the globe, with others doing the same.

In other pockets, some people won't be as contemplative as Mr. Cool, and will try futile resistance, not ending with their deaths, but merely their futility, as we see "Thing sensor people" watching them on video and laughing at them, even playing jokes on them.