I wish Bennett didn't rewrite the script because I think that was a great idea and a natural follow up to Star Trek II. I wonder how much of Kirstie Alley's character would've been involved in that script? She was such an impactful character and I was gravely disappointed by Robin Curtis's portrayal--she was a completely different character and I was glad her brief appearance in IV was just that. Expanding the Romulan characters would've been a direct connection to Kirstie Alley's Saavik and may have explored her origins a bit. This outline was a great idea; far more promising than what I saw in Star Trek III... for me, a very, very VERY disappointing follow up to the magnificent Star Trek II: The Wrath of Khan.
I don't know if they went down a different route because the story was leaked, or because they just wanted a simpler story. It's an interesting outline for a potentially more ambitious story which would have still resurrected Spock. I agree that Robin Curtis's Saavik is a different character than Kirstie Alley's Saavik. Kirstie Alley gave the character more humor and emotion while Curtis made her a straightedged Vulcan. I thought Curtis was good overall but I never liked her "David is dead" delivery. That seemed a little cold.