I just saw a post that deeply annoyed me because it went, "Here's a story that's like a Regency romance, but I FIXED it by making the characters sexually liberated and shame-free and polyamorous!"
This is like saying, "Here's a story that's like a thriller, but I FIXED it by having the serial killer go to therapy instead of trapping victims in his evil maze and dismembering them."
The thing a lot of people don't seem to get is that the entire appeal of a Regency romance is watching a deeply repressed, perfectly controlled, buttoned up, straight-laced person who has never expressed an emotion before fall so hard for someone that something in them just breaks and they come completely unhinged.
It's a very specific kink that this genre is tapping into.
People who think the characters in a Regency novel are boring are missing the whole point. The characters are supposed to be boring, right up until they fall so madly in love that it drives them insane, at which point they become very interesting. Regency romance novelists are doing the writing equivalent of putting plain white featureless uncooked whole eggs in a microwave and waiting for them to explode.