Gotham Central wrote:
1) Why weren't more of the aliens depicted in the RecDeck scene used in other places in the film?
According to Fred Phillips, during a phone call I had with him in January 1984 (he had once promised meeting me for lunch, but was legally blind by the time I got to the USA), the original brief was for him to create lots of colourful aliens that could be used in a banquet/briefing scene that was reminiscent of "Journey to Babel". While he was experimenting with recent advances in slip latex, so different to the old methods, he designed both over-the-head masks (which wouldn't have permitted the extras wearing them to talk), and a few aliens (Rhaandarite, K'Normian and revised Andorians) who could deliver dialogue if required.
Of course, no version of "In Thy Image" or TMP had such a scene, and both Billy Van Zandt (as a Rhaandarite) and Paula Crist (wearing a female version of a wolvish male alien she had once created at a convention) screentested as the scripted "alien ensign" who would be regularly seen on the bridge.
The Rec Deck scene gives the impression of a fairly diverse crew for the Enterprise, yet once she is underway, just about all of the aliens disappear
Because the aliens in the rec deck scene represented one big day of filming, with an emergency team of extra SPFX makeup artists helping out. It would have been prohibitive to keep populating scenes with aliens, and most of the movie is set on the bridge. Poor Billy Van Zandt had 5.00am makeup calls over three months for (one line of dialogue that got cut from the theatrical version after all) as it was.
There was also the point that, when the director was finally appointed, Robert Wise didn't find the over-the-head-masks convincing enough, and he relegated them to mainly-distant shots, especially in San Francisco.
if Decker were in command of the ship, then I'd assume that he'd be in the center seat and Kirk would be standing around to direct the mission itself, which also isn't what audiences paid to see.
And, in the planning for "Phase II", they knew they only had a commitment from Shatner for 13 episodes
. He was anxious to kickstart a career in motion pictures. The actor yet-to-be-cast as the Will Decker character was to be groomed to take over as lead actor if Shatner chose to step down and do only semi-regular appearances.