Crikey! Putting aside the merest hint of the whisper of a likelihood of a possibility that Waugh may just be cranking up a tired old historical theory in order to up sales for his latest book, just what is the "unnoticed evidence" in "words not especially ambiguous", that is, "by Elizabethan standards" that he's referring to? Possibly this:
William Covell’s epistle appended to *Polimanteia, or the meanes lawfull and unlawfull to judge of the fall of a Commonwealth, against the frivolous and foolish conjectures of this age* (1595) which offers a printed marginal note containing “Sweet Shakspeare” near the text “Oxford thou maist extoll thy courte-deare-verse” which of course means Shakespeare is Oxford via an anagram for “courte-deare-verse”.Er, right ho then. But before we acclaim De Vere as the author of all that play stuff and sonnet stuff and other stuff, the author of that blog post points out that "courte-deare-verse" anagrammatises not only to "our de Vere - a secret", but also many other phrases.
Anyway, after reading this piece by Waugh, I had a little toddle around the sites myself. Like Greg Hunt, I only use the finest evidence Wikipedia has to offer, and it certainly had something to offer in this instance. Shakespeare died in 1616. De Vere, the poor sausage, carked it some 12 years before, in 1604. And turns out that several of Shakespeare's plays - including King Lear, Macbeth, and The Tempest - were written, according to dating by scholars, after 1604. So to write all those plays on the sly, De Vere had to either rise from the grave before putting pen to paper again, or pop into the time machine a month or so before his scheduled death, go forward a couple of years, and write them. Which puts rather a dent in the the "authorship question" that Waugh is trying to fire up, don't you think?
Then again, a fun alternative little theory that Alexander Waugh might like to entertain is that Shakespeare had hot gay sex with Edward de Vere, wrote about it at length in his sonnets, and had this William Covell chap hint at it as a shared secret in his book. What do you reckon? Such a lubricious detail might help to sell a few copies of the latest work from the Waugh clan too....