What transactions are going to be involved in your "transaction universe"? There should be highlights and data flow diagrams with regards to that I think so that 1. Developers would easily understand how much better and simple it will be and 2. Users would know what transactions would be involved and how easy it will be compared to existing systems.
Well, simple transactions probably, the ones normally applicable to app stores: purchasing apps, in-app purchases, advertising, app development and sale related transactions.