Clarify doc wording

docs/api-reference.md

@@ -214,7 +214,7 @@ function MyComponent:init()
 end
 ```
 
-In older versions of Roact, `setState` was disallowed in `init`, and you would instead assign to `state` directly. This is still acceptable, but it's simpler to use `setState`:
+In older versions of Roact, `setState` was disallowed in `init`, and you would instead assign to `state` directly. It's simpler to use `setState`, but assigning directly to `state` is still acceptable inside `init`:
 
 ```lua
 function MyComponent:init()
@@ -298,7 +298,7 @@ Setting a field in the state to `Roact.None` will clear it from the state. This
 	* Lifecycle hooks: `willUnmount`
 	* Pure functions: `render`, `shouldUpdate`
 
-	Calling `setState` inside of `init` or `willUpdate` has different behavior in other places. Because Roact is already going to render or update a component in these cases, the update will be replaced instead of another update happening.
+	Calling `setState` inside of `init` or `willUpdate` has special behavior. Because Roact is already going to update a component in these cases, that update will be replaced instead of another being scheduled.
 
 	Roact may support calling `setState` in currently-disallowed places in the future.
 

docs/guide/state-and-lifecycle.md

@@ -34,7 +34,7 @@ end
 
 In this case, we're passing a _function_ to `setState`. This function is called and passed the current state, and returns a new state. It can also return `nil` to abort the state update, which lets Roact make some handy optimizations.
 
-Right now, this version of `setState` is exactly the same as the form where we pass an object. In the future, Roact will support a number of features, like asynchronous rendering, that make the distinction more important.
+Right now, this version of `setState` works exactly the same way as the version that accepts an object. In the future, Roact will support optimizations that make this difference more important, like [asynchronous rendering](https://github.com/Roblox/roact/issues/18).
 
 ## Lifecycle Methods
 Stateful components can provide methods to Roact that are called when certain things happen to a component instance.