Disclaimer: I do firmly believe that William Shakespeare wrote the plays and poems attributed to him, and some of them in tandem with his fellow playwrights.
The keep an open mind argument really grates on me as it implies something is wrong with those who don't agree. I'm quite capable of analyzing data and discarding faulty propositions. I have done a lot of reading and research on this issue and there is 100% nothing to it. The entire argument is based on either making untrue statements or by revealing incomplete or out of context information and thereby making something sound compelling which is not in reality meaningful. For example, there is no extant written document in his hand other than signatures on several documents. What extant plays, letters, diaries exist for other playwrights of the day? Other than Ben Jonson there is almost nothing. One possible signature in Marlowe's hand (spelled Marley) and one possible scrap of paper with a few lines from a play on it. There is not a single extant handwritten example of a play which was published- the only ones that were saved were the single handwritten copies of unpublished plays. Shakespeare did not own his works so there was no reason to mention them in his will; they had no monetary value. Books were listed on the inventory of the will and his is lost. In any case, why is the only sufficient proof of authorship a handwritten play? If that's what's necessary, how can it be that no handwritten play of DeVere's has come to light? How could he not have saved and hidden them away? How could he not have at least safeguarded the plays he produced under his own name? Shakespeare's plays were performed by his troupe and they were published with his name on them. Many people of the time who were involved in the theater and personally worked with him and knew him agreed that he was the author of the plays attributed to Will Shakespeare, the Sweet Swan of Avon.
I have looked into the "authorship question" very thoroughly (Edmondson’s and Well’s book is just another one among many on the subject; Shapiro’s “Contested Will” is much, much better and much less dry than this one) and I find no good evidence at all that Shakespeare's works were not written by William Shakespeare of Stratford-upon-Avon, despite the all too familiar claims of a very vocal minority with nothing better to do than to indulge in conspiracy theories. I do not intend to waste any more time on it here - I am off!