That is not a proof in itself apart from the fact that, because it was technical, it needed errata. 3e was technical, 4e was technical, PF is and was technical, MtG is technical, they all need a huge quantity of errata because of that simple fact. Were absolutely all of these "badly put together" ? No, they were not, it's again all these fantastic designers on the internet who have zero published games to their credit but who just like to brag that they would have done better, nothing more.
Thankfully, 5e adopted a very different trend, wanting to be not technical at all, with no jargon, which not only made errara much less necessary, but also happened to please a much greater population. But I'm sure you've noticed that, despite the fact that there are very few errata, there are still people around claiming that it's terrible design...