That's not a bad idea: a diagram of extension processes - a flowchart of how the extensions can compliment each other to produce various outcomes.
In addition to clarifying for users which extensions they should use, what for and in which order, it would also enable a visual guide for prospective purchasers to decide what it is that they need buy.
At the moment - browsing the products' overviews ("Do you need your form to send an email or submit to a database? Check out the WebAssist Extension Library Membership Program which contains all the Dreamweaver extensions you may require.") is a bit of a maze, involving a great deal of reading to finesse one's precise needs.