A few things. At least when I wrote it, the very first step you'd see the friends who tried to connect with you, if you have any. I doubt that's changed, so this may be a special case.
After building this flow, I helped my team design multiple better/more modern flows, but all performed worse than my original when we measured for retention over time. It turns out it's much trickier than it looks to build a better flow, and it also hard to prove that it's better due to bots/spammers.
Even though this flow is far from perfect, I still take pride that my face has been shown to hundreds of millions of new users, and that it greatly outperformed its predecessor. But I just want to remind users here that it's easy to say: "This is crap, I could do better." When it fact, many other "better" things have been tried, and it's surprisingly harder and more nuanced than it looks.
With my knowledge now, I believe more of Twitter's energy should be spent improving the product, because the new user flow is much less important than the product people see when it's done.