With Data, however, you don't seem to get the hero worship / role model thing that Janeway (inexplicably to me) appears to generate in her fans. Data was a great character that I miss. I suspect most fans feel similarly, but that's it.
Janeway (and yes, my opinion is coloured by my dislike of Kate Mulgrew as an actor) was badly written,
inconsistent and annoying. I cannot deny that something about her connected with her following, but it almost seems like a mother / sister / mentor relationship her fans project onto the character.
For a large number of Janeway fans being female, by and large it's simply the appeal of a strong, independent, female leader, which in Trek or any other fictional realm or in reality even today are few and far between. These type of role models show young girls a positive influence and that they can achieve great things. Janeway as with other heroes, became a beacon of different things to different people.
It can't be denied that Kate Mulgrew was a path setter by portraying Janeway. She opened many doors for other women in sci fi. I also believe her fans loyalty comes from how she interacts with them and how approachable she is. I am on the opposite end of the spectrum where I just don't understand how someone could not like her, lol. To each their own.
Firstly, it's nice to enter into a civilised discussion on this topic !
You are right that it was about time there was a female Captain in Trek if gender bias is truly be a thing of the past by, er, the future ! There have been strong independant female characters in pre Voyager Trek - I am particularly fond of Kira, but even if higher in rank (i.e. Admiral Nechayev) they were never 'in charge' on the show, i.e. the Captain...
I would have delighted if Janeway had been written better in a better show - I can't really move past the lack of quality and care in the making of Voyager. The lack of character development, silliness with power rationing yet use of the holodeck, infinite replacement of torpedo's and shuttles, battle damage disappearing, acceptance of Maquis crew, Maquis / Equinox crew that were never seen again etc. etc. all kill Voyager for me. In addition, Kate Mulgrews mumsy Hepburn thing just grates on me (yes, she may be a very nice person and could just happen to speak like that) but that's my take.
As I see it, Janeway did women a disservice - it was time for a great female lead character, and she wasn't it...