I think Shatner had Goldsmith hired earlier on than is often the case, because on other shows, they had to go with cheap composers (horner for instance) because there was no money left in the budget for 'real' composers. So this was a case (like the great new phasers) where money spent up front ultimately may have hurt the movie since he didn't have any money to do the climax, especially after the budget restrictions mentioned in the makingoftff book that were put on later in preproduction.