I was skeptical of buying into the light table idea until now. Now I see it for what it is: A programmable debugger with a dashboard for your software, as well as an editor, the latter part being less important. It's like if gdb had a baby with some visualization app.
The debugger already is omniscient in terms of what is going on within the program, but it's inept at showing it to you. It's too low-level in that it doesn't know what specific entities are important in your program. It knows addresses, variables, maybe objects. But you have a mental model and instead of trying to get your mental model into low level terms you can program it to have some notion of what to display.
I've spent the last decade writing debuggers; they are anything but omniscient. It's a miracle that they work at all, frankly.
In principle gdb could look at everything that's going on, but in practice doing so would (a) hit a bug in the compiler's debug output and fail, and (b) take forever for any program worth debugging.
Most debuggers are technically not omniscient because they don't trace history. IntelliTrace is better in this regard, but you can see projects like LightTable taking that to the next level.
The debugger already is omniscient in terms of what is going on within the program, but it's inept at showing it to you. It's too low-level in that it doesn't know what specific entities are important in your program. It knows addresses, variables, maybe objects. But you have a mental model and instead of trying to get your mental model into low level terms you can program it to have some notion of what to display.