What if Halsey's Third Fleet had stayed near Samar?

How would Samar have changed if Halsey had not taken Third Fleet north?

It likely becomes an overwhelming fleet confrontation, but that also means the Japanese decoy has failed to draw away the American force as intended.

Keeping Halsey's Third Fleet near Samar would have changed the scale of the encounter much more than adding one command cruiser. The proposed result is probably a battle of annihilation between American and Japanese forces. That prediction remains a counterfactual. Drawing American forces out of the way was part of the Japanese plan to obtain a passage through.