Why did shakespeare's contemporaries recommend rereading his works, and what might this information suggest to current readers?

Shakespeare's contemporaries recommend rereading his works as it is worth the effort and also eventually we will come to understand them.

Explanation:

Michael Mack's essay or speech "Why Read Shakespeare" is an interactive explanation of why Shakespeare should be reread. His contemporaries, especially John Hemings and Henry Condell, whom Shakespeare refers as "my friends" in his will, recommend it because they recognize that even though his works are difficult and sometimes incomprehensible, one should reread as it will be worth the effort. Just like a music that isn't understood at once but makes sense after listening to it so many times, so is Shakespeare. We can understand the real thing if we take the effort to reread them.  

This suggests that after continuous and re-readings of those confusing passages of Shakespeare, we will be able to fully understand everything eventually.

faulty parallelism is a grammar construction where there is no balance in the parts of a sentence they have a similar meaning but the grammar structure is not equivalent.

the correct version of this faulty parallelism in the sentence is:

jefferson wrote the declaration of independence, and he was the nation's third president.

the problem with the first version is that the sentence:

"jefferson was both the writer of the declaration of independence"

presents jefferson as both a subject and an agent for the verb "write" because if he was "the writer" then the declaration of independence was written by him, besides that fact, the sentence presents a dependent clause.

while the second sentence:

he was the nation's third president.

presents a basic subject+verb+object structure

so, to give a proper balance to the structure, or better said, to give a parallel structure, we must write a basic s+v+o structure in both sentences:

jefferson wrote the declaration of independence, and he was the nation third president.