Natural language is the most powerful (kind of) language we have, because using it we can generate narrower and stricter languages (mathematics, for instance) and communicate their semantics to fellow humans.
But natural language can express a lot of things that are imprecise, like "huh?" or "well, you know...", or, say, profanities. So a somehow less powerful language, with some restrictions requiring politeness and clarity, is easier to understand. That's the point of the original article, broadly.
That's what I mean by "harnessing" the power. Restricting the language by simplifying it, switching to baby-speak, is what I'd like to avoid: while less powerful and not allowing for many potentially dangerous constructs, it remains imprecise, but loses the ability to express complex things concisely.
Not really though. “Dynamic typing” is really just having a single type for everything. Is quite easy to express in a language with variants. Of course, you don’t usually write code like that in a typed language because then your giving up the value of the type system.
But those things are already widely popular, someone saying "we need less powerful languages" means they want even more than that, I'm not aware of any things that aren't currently popular that would improve these things by a lot.