I realise it has the best of intentions, and nobody is proposing to remove 'to be' from everything. But the discussion here about how adopting E-Prime forces you to rethink what you mean to say, is eerily reminiscent of how Newspeak was used to control people's thought process.
The idea behind it is supposed to show that by removing the verb 'to be', you have to think more on how to properly convey what you actually mean.
So in a sense it even allows you to get your actual thought process out there rather than having it dismissed for sounding overly harsh for example.
Contrast that to Newspeak, whose design is to limit and shape people's thoughts by external means (Another person chosing what is ok and what not), where as here /you/ get to choose what you say, it is merely the form that changes.
To be more explicit:
1. Do people 'think in a particular language' such that limitations in language limit their thought? This is something that psychologist have considered. The other comments in this thread suggest to me that there might be something in this.
2. Is it dangerous to allow any kind of authority that tells people what they can/can't say? If the answer to #1 is 'yes' then would such a group be too powerful to be allowed to exist?
The people who wish to do this are labouring under a great many sceptical confusions and take saying ordinary things like "the pen is red" to be some god-like act. Ie. they wish to subjectivise everything.
It isn't god like at all, and we're not trapped within our own subjective nightmarish experiences for every doomed never to be talking about the world.
It's a very simple thing to make a claim about how the world is and for it to be true (eg. "the sun is aproximately 8 light minutes from earth"). Rewriting language on the basis of some mistaken sceptical pet-principle is the height of absurdity.
cf. http://blog.mjburgess.co.uk/2015/12/objectivity-and-humility...
4. Never use the passive where you can use the active.
All rules are there to be broken
6. Break any of these rules sooner than say anything outright barbarous.
http://www.orwell.ru/library/essays/politics/english/e_polit...
Orwell writes essay advising writers to remove undesirable vocabary, part of which OP is an extended exploration.
Irony
All language shapes thought. This is the "Sapir-Whorf hypothesis".
"Newspeak" was an attempt to use this principle to shut down thought by taboo-ing entire classes of concept.
E-prime is an attempt to provoke thought by taboo-ing a single concept.
There are good and bad uses for everything.