If you're going to assert a link with another movie, especially if you're viewing it negatively, it might have been a good idea to actually see that other movie. In any case, I hope you do because The Thing is a great movie.
And to answer your question, no, I think it was a great addition. It introduced a solid, scientifically plausible reason for why the alien was so adaptable, and therefore posed such a threat. Having the ability to steal thousands or even millions of years of evolutionary specialisation in a single generation, while simultaneously accounting for evolutionary weaknesses with their own inherent traits makes the potential for the alien species virtually limitless.
