It sounds like your opening pitch was for solving problems that your visitors didn't have. That's an age old problem. You fixed that. Then, once you got a bit more of their attention, you started to elaborate on the product. This too is not much of a novelty. That's good old gradual on-boarding, "gentle introductions" and what have you.
They are still mentioned on the homepage and in a form of a carousel at that.
I appreciate that this must've been a significant rework, with all edge cases considered, but sectioning off parts of a software and making them discoverable in a course of normal use is not exactly novel... I mean that's just too bold of claim to be thrown around lightly. The story is still interesting, but something a bit more exact like "Here's what worked for us remarkably well" would've been more suitable.
I think an added benefit is that it makes it trivial to see what are indeed the benefits of the tool : it's what you expect from an email client plus those things, nicely presented together. Just by reading the article and seeing the screenshot, I could evaluate if I was interested in this tool, which is a very rare thing.
If there's nothing novel in the initial version why would people think they would want to switch? What would be the reason?
Could it be that your product without any unique features is cheaper than competition, and adding features costs something?