^ No Klingon? Well, remember, David Gerrold said "Throw in a bit of Klingon and then you've got a story"... or something like that. I've always said Dorothy Fontana's idea was better, to throw in Romulans instead.
But, second? I'm assuming you refer to TWOK as the only movie without a single Klingon, as TMP had real Klingons, III had Kruge, Maltz & Co., and IV had a brief bit of Klingon Ambassador protesting.... V had Korrd, Valkris, and what-his-name... VI was about the Klingons... and everything else had Worf. Do we really count Worf in all of those? Q was right about him, he can't even get a shot off most of the time.
ENT's explanation though doesn't rule out ALL ridged Klingons. There could be Chang-like Klingons too...