Reverend Jim made a pretty menacing Klingon.
Even then, you'd think they would have noticed that half his roles to date had been anything but goofy or comedic.
Lloyd established his ability to be scary, and amped it up two years later in the Amazing Stories episode "Go To The Head Of The Class" as the English teacher from Hell.
Lloyd was also a great creepy villain as Butch Cavendish in 1981's
The Legend of the Lone Ranger. The movie's not very good, but he's good in it.
It's kind of a shame that Lloyd is mostly remembered today as Doc Brown, Reverend Jim, and (maybe) Judge Doom from
Roger Rabbit. He's much more versatile than that.
The long-circulated story is that Leonard Nimoy never wanted Christopher Lloyd for ST III. He wanted his friend
Edward Olmos. But Paramount had given Lloyd a pay-or-play contract to keep him on
Taxi another year, and it was "times up." They didn't want to pay Lloyd a bunch of money for nothing, so they stuck him in ST III. It worked out well enough I guess.
Interesting. I knew from Shatner's
Star Trek Movie Memories that Nimoy wanted to cast Edward James Olmos, but Harve Bennett disagreed with the choice. I hadn't heard about Lloyd having a pay-or-play contract for doing another season of
Taxi.
Star Trek II also needed to appeal to a general audience, not simply Star Trek fans. That really narrows down the pickings.
Yes, true. You need a good hook for the general audience to latch on to.
Star Treks II-VI all had that with "Khan is back and he's out for revenge!" "We're bringing Spock back!" "The crew's traveled back in time to 1986!" "We're going to find God!" and "It's the last movie with the original cast & we're making peace with the Klingons!"
"Mirror, Mirror" -- a doppelganger invasion, a la DC Comics Star Trek run set between TSFS and TVH...
In terms of a sequel hook, "Mirror, Mirror" is probably the biggest one in TOS outside of "Space Seed." But the second movie probably would've been a bit too soon to introduce general audiences to evil counterparts to the crew. The movie series was still struggling at that point.
But a "Mirror, Mirror" follow up is something I was
dying to see in the mid 1980s. I remember around 1986-87, I was making doodles of Movie Era Mirror Universe uniforms, and imagining a follow up to
Star Trek IV called
Star Trek V: The Other Side, a loose adaptation of Mike W. Barr's Mirror Universe Saga from the DC Comics series. I had an opening scene in mind with Mirror Spock and everything.