My 2¢ worth; based on teaching programming (with FB) to high school  
students for a few years.

I found a spiral approach based on themes/topics rather by keywords  
worked with my classes. Keywords & topics would be re-examined in more  
detail in subsequent chapters as the need arises.

For example - printing in a window.
a)  Simple PRINT with text
	- simple window and pause at end
b)  PRINT with numeric variables (after introducing them)
	-Good time to introduce FOR loop too
c)  PRINT with text variables
d)  INPUT with variables
	- calculations and storing results (basic math, order of operations)
	- PRINT results
e)  ....
~)  Using Static edit fields for (self-refreshing) text messages & to  
position message
         (skip @ option of PRINT, ok for beginners maybe but not modern)
     Using Edit Fields for input
     Using buttons and subroutines to perform actions - with data in  
edit fields

The indent was to teach programming principles using features of FB  
rather than to teach every option of each instruction/keyword. I can  
see a need for a complete technical reference re Keywords but there is  
a greater need imo for a beginner's guide showing how to use related  
instructions and develop a program that accepts input, processes it,  
and creates results. Using increasingly detailed examples with math,  
text, and especially graphics is one approach to this.

Another example might be Working with Windows. Rather than being  
isolated in its own chapter as I've seen in some books, all that is  
need early on is WINDOW 1.  In a subsequent chapter, introduce the  
options for setting the window's size and title. And later on, how to  
create additional windows and switch between them as needed. Trying to  
learn all at once is daunting.

As I said, my 2¢ worth of observations re structure of a guide for  
beginners to FB. Wish I had more time to devote to it, and to focus on  
FB5 too. <Sigh>

Good luck with the FB WIKI project.
-Stu