I think it was actually the other way around for many people - for all the avid Star Trek fans, when TNG first came out everyone was up in arms that they had "changed things".
At the time that ST:TNG originally aired, I didn't have any friends who were genre fans. My husband and I weren't even genre fans then; we were what you would consider mainstream. So I'm coming from that perspective. As I recall, mainstream media was solely focused on whether a decent show could come out of a 20-year-old idea and they were surprised that it did.
Now that I have more geeky friends, I am not surprised that they picked ST:TNG apart :-). Honestly, I'm surprised that more of them haven't picked the new Doctor Who apart. Genre fans have long memories and to them, writers better have a darn good reason for changing their beloved shows. That's why I would never be a good geek -- if it is even mildly entertaining, I'm good!