"To be, or not to be, that is the question."
Prince Hamlet asked.
My answer: Not "to be."
Why? Because any form of "to be" — is, was, am, are, were, has been, etc. — delivers the weakest verb in the language. Sentences that perch on a "to be" verb tremble like a reed in a soft breeze.
What makes your choice of a verb so important? A while back, at Colorado College, I met the journalist in residence, Hampton Sides, a leading writer of nonfiction. I had just read an article he'd written, and I told him I could feel the power of his verbs.
He said, "Verbs rule."
Consider this example of a "to be" form that afflicts so much writing: "I am of the opinion that the city needs more parks."
Far better to write, "The city needs more parks."