We never were worried about change before.
The "redesigned and refitted" Enterprise, its destruction and its being replaced by the Enterprise-A, TNG, DS9, Voyager, even Enterprise...
I wouldn't say Trek fans are frightened of change.
Huh?
I became a ST fan in 1979. I was staggered how many 60s ST fans were critical of
every change in TMP: the Klingons' makeup, the uniforms, Spock's brown hair instead of black, the uniforms, the wrist communicators, the Perscan buckles, the transporter effect, Kirk's promotion, Spock's supposed rejection of his human half, McCoy's resignation, Chekov as a security chief, Ilia as navigator, Decker as captain...
Spock's death in ST II had fans book a full page ad in "Variety" to complain about Spock's death, and that campaign was reported in the "Wall Street Journal", with fans calculating profit losses for Paramount if Spock died. Nimoy reported receiving death threats in the mail.
They changed Saavik actresses in ST III (and her hairstyle, eye colour, eyebrows and approach to line delivery) - and people again complained. Not to mention Kirk destroying the Enterprise.