Maybe Harve Bennett's original outline would have been the best route. The following is from memory-alpha:
According to an article on io9.com, [2] Harve Bennett's original outline for Star Trek III would have involved Romulans coming to Genesis instead of Klingons and them finding the world very rich in dilithium. The Romulans then begin to mine the planet until the miners begin being killed by a feral Spock, whose aging was still tied to the aging of the planet. At the same time, Vulcan, upon hearing of the Genesis Device, is so horrified to discover that the Federation created such a potential weapon they want to secede from the Federation. This would have sent Kirk to Vulcan, with the crew of the Enterprise, to face the angry Vulcans. The article states that Robert Meyer Burnett, CEO of the Ludovico Technique and producer of the Star Trek: The Next Generation Blu-ray DVDs, felt like this would have been a more serious, "perilous" and above all epic story than the actual produced and released film – and it would have featured a Romulan commander along the lines of the thoughtful antagonist from the original Romulan story, "Balance of Terror".
In an early draft of the script, the Klingon Bird-of-Prey was originally to be a stolen Romulan vessel (the red "feather design" of the wings' underside was designed with the original Romulan Bird-of-Prey in mind), but that detail was dropped from the final draft.
A copy of Bennett's original storyline was leaked to fans in February 1983, forcing him to rewrite the script, changing many of the film's original details and events.