Question

What is the main scientific weakness in watson and crick's paper?

Answer 1

One weakness of their paper is that much of the work was drawn by Crick's wife and she was not credited. They also do not answer the concern of what makes complementary nucleotides rotate in space, thereby producing a DNA spiral.

Answer 2

When writing a scientific paper, it's ethical to refer to those who helped you in your paper and to cite all the references you used in order to give credits to the owners of these references.

In Watson and Crick's paper, they did not refer to those who assisted them in their research neither gave them credit. This is somehow considered as stealing someone's work and referring it to yourself.
This was the major scientific error in their paper.