Glad to see this project is going to be brought to completion - I like the flavor of it quite a lot and Fax had a great start to it.
Warspeaker, I would say, is better than Knight-Scholar, simply because Knight-Scholar doesn't really have any... it doesn't sound like a class to me, it more sounds like a description of someone. Like say, something that would be said of Saladin or something.
I did playtest this material as a martial focused Advocate (heading to rhetorical blade) for about five to six levels in the Skull and Shackles AP. I found that one issue I had was that I had almost no way to realistically meet the cadences even with an intelligence score of 20. My Tzocatl check bonus was never enough to have any feel that my edicts would ever get improved - it was my assumption that they would just provide the base effect, which is alright, but quickly was falling off. I'm not sure really how to fix this, but I feel that there's something to be said for a little bit more predictability when it comes to using your edicts and improving them - especially with the rules saying that you have to choose which cadences to use before you roll your tzocatl check. I really wanted to light tzocatl, but had a lot of trouble to do that. Often times, I simply felt like a worse fighter that could cast worse spells than if I had been, say, an inquisitor or bard or other d8 class. Not that the Advocate has to match that same balance level, of course. Just an example of how I felt constrained by the checks and rules.
I really wish I could offer some concrete suggestion, but basically all I have was that experience.