And Robert Wise suggested that Ilia herself was actually a last-minute replacement navigator for the woman officer who died in the transporter accident, explaining Decker's surprise at seeing Ilia. Roddenberry's intent for the deceased female character may have been different, as in his novelization she was Vice Admiral Ciana, who had been in a temporary marriage contract with Kirk. And Kirk has a rather, um, sentimental reaction on seeing her on the comms some time before the transporter accident.
Kor
I saw the part about Kirk's wife and was surprised, I didn't know that bit of Beta canon existed, but I never thought much of Ilia being a replacement. That makes so much sense, as you'd think Decker, who was the Captain of the ship like 5 minutes earlier, would know who was coming onboard.