Star Trek fans have become very sensitive to introductions of new characters, aliens or historic events arguing that things that haven’t previously been mentioned ‘break canon’ or disrespect lore.
This piece by Inverse shows how profoundly TNG retconned Federation, Starfleet, and main characters’ history on the fly.
Worth thinking about.
I’ve been sitting on an essay concept for a few years now, all about how TNG was secretly (and unintentionally) about the end of an era of peace, and the Federation being shocked out of complacency.
The retconned Cardassian war (and to a lesser extent, the Tzenkethi conflicts) is the biggest challenge to address, but their very existence kind of supports the underlying notion that things were never as good as is popularly believed.
All of which is neither here nor there, and I think your point is a good one.