To me, Neil always seems like he's talking to children.
This is great for children. But as an adult who already knows 95% of what he's talking about it comes across as a bit grating.
Carl Sagan could tell you what you already knew, and you'd still be happy to hear it, because he'd just remind you how awesome this stuff you already know actually is.
I hope that the sequel also targets a sophisticated audience: those of us that loved the original when we were kids and have continued evolving our brains for decades.