Value Lists should have an option to be a calculation. Right now you can provide a manual list or you can select a field to essentially get the index of that field or 2nd field, etc. But this is actually a bit limiting.
Most things in FileMaker work with the calc engine (e.g., calc fields, conditional formatting, hiding, etc., etc.). So why not give an option for value lists to also be a calculation. You would have to set context by selecting the table occurrence to base the calc on. But it would also give the flexibility to even use ExecuteSQL calls, which I think would meet most of my value list needs and be very powerful. Plus this would follow the normal calc implementations used throughout the FileMaker framework and provide for consistency.