How useful would knowing the AI would be using, say, A* search, as opposed to meta reasonings on what it is likely to be searching for? We know both from computer science and our own minds that effective heuristics exist to approximately solve most problems. The precise bottom up knowledge you refer to is akin to knowing that the travelling salesman problem can only be solved (assuming NP not P) in exponential time; the meta-knowledge "good polymomial time heuristics exist for most problems" is much more useful to predicting the future of AI.
The issue is not merely that you don't have ground up definitions which respect the time constraints. The issue is that you don't seem to have any ground-up definitions at all, i.e. not even for something like AIXI. The goals themselves lack any bottom up definitions.
Worst of all you build stuff from the dubious concepts like that monolithic "intelligence".
Say, we want to make better microchips. We the engineers have to build it from bottom up, so we make some partially implemented intelligence to achieve such a goal, omitting the definition of ...
It's just occurred to me that, giving all the cheerful risk stuff I work with, one of the most optimistic things people could say to me would be:
"You've wasted your life. Nothing of what you've done is relevant or useful."
That would make me very happy. Of course, that only works if it's credible.