There’s this never ending battle between two camps:
In the left corner we have team WOW who insists that it’s mainly how you say something because crappy ideas beat brilliant ideas when they are communicated better. (Which, indeed, frequently happens.)
In the right corner we have team AHA who insists that it’s mainly what you say because there’s no “how” without a “what”. (Which is true but also the reason for why team AHA frequently loses.)
Great communicators don’t really care for this battle, though. It’s obviously pointless to have a relevant message when your audience can’t see the relevance. It’s just as pointless (but more profitable) to have a message that’s awesome but which the product can’t deliver on.
Therefore it’s both. It’s how we say what we say. We need highly relevant messages (the what) that resonate deeply (the how).
Work rigorously towards this goal and results will follow.