I like the way you think! Yes, it is not a question of whether or not we can expose an API that would let you do everything the UI does via backend program calls, but whether or not you can isolate a subset of simple, often created cases, and then simplify the creation of those.
Clearly, that is doable. Before I go further down that line, though, I would like to point out that we plan to make Quick Build extensible. That is, you can take an existing test definition and Save As a Quick Build template. I think that it is possible we could use this approach to help you, um, quickly build out common, oft-needed tests.
Now, having said that, to do the API we need several things:
A list of what the common cases are - Code Tester users could help LOTS here and I encourage to think about this and reply on the forum with your ideas.
Development cycles (bandwidth) to build this. Such cycles are tight. I am totally amazed that even in its extreme youth, Code Tester already has an ER list several years long!!!
On the other hand, writing backend code is much, much easier than building UIs, so this could move quickly. Hey, especially if we could find a way to have some of our users (PL/SQL-pros that you are) help us build the APIs!