I recently heard a discussion that one of the indicators of God's being creator, and not the cosmos itself being its own 'creator', or processes within the cosmos being required to give effect to God's fiats in Genesis 1, is the parsimony of action implied in Genesis 1.
That is, a clear result of intelligence brought to bear is the economy of effort that is applied.
This is echoed in a number of passages in the Bible:
The centurion's servant is one. The centurion expected instant results from Jesus' command, just as he expected from his troops.
There are also examples in the Psalms:
Psalm 33:8-10: he spoke and it happened!
Psalm 148:5: same as above!
Genesis 1 itself indicates parsimony of causative effort: God spoke...and it was so!
I don't think this leaves much room for setting aside the implications of rapidity in Genesis 1.
