Nothing, actually, it's a quality library, just old.
I can think of a few algorithms that have changed or been created since the 1990s so I have to assume there's something that can be done to optimize it.
There's also a severe lack of "in-browser" CV solutions (which could be fun), instead opting for binding OpenCV in the server-side.
Same here. I was thinking of how long it would take us before the inflation in fancy CVs and resumés would force recruitment agencies to invest in rendering farms and full-body VR suits in order to read job applications.
I don't mean to criticise you personally, because I have done the same thing, but: Comments about what someone thought the title meant are very common and not interesting in any way.
I disagree. Most of the reason that people click on anything on this site is directly because of the title, so if I have particular expectations that the title fails to meet, then it's fair game for commenting. I don't think it's fair to assert that what you find common and uninteresting is irrelevant to someone else.