Of course it was a joke, she's a exaggerated depiction of an idol. I'm not sure how anyone can consider someone like her to be serious. And yeah he knew what reaction it'd get and decided that he was gonna have fun with the outrage. It'd be naive to believe otherwise.
Following trends is what every game does and has done. Tekken isn't any different. Kaz is the go to Karate guy. Nina's the 90s blonde action girl. Law is Bruce Lee. Lei is Jackie Chan. It was trendy to make fighting archetypes in the 90s. Now it's fantasy. People just simply don't like the current trends which is fine.
Reason I can accept it is because ultimately, it's not a big deal. As long as the older guard is still around, nothing wrong with more modern characters.
You are missing the point, the character itself wasn't the intention. It's the concept behind the character in it's design. Harada made the indication that he was merely joking to "make" the character "upon creation" because he had his hands tied to making one due to the push of Tekken 7 and demand. Lucky Chloe wasn't even the true intention of the problem here but merely an accident that "still worked" and thus made a general name for the character getting put in, named "Lucky" Chloe. You can thank Kotaku and Shoryuken.com for figuring out that hint while Harada confirming that it is indeed true with him joking on "making" the character and that he wants to save time to develop the game for the arcades for production and feedback on gameplay. From there on, he focused on Lucky Chloe's moveset and general base frame data.
Nina was thoroughly made in design and character, Kazuya was thoroughly made in design (Mind you that he was originally suppose to be the main character, but fans wouldn't like a darker tone protagonist so they changed it to someone else who is a natural hero with a dark secret -somewhat-) other characters cannot play the victim here when they were made for the "default" game in itself. It is not because they do not like the current trends (somewhat common problem, not a major one), it's the change and forcing oneself to fully indoctrinate and giving into things where you don't necessarily have to.
Not against the removal of characters here, but merely pointing out that she wasn't exactly intended, but he gave the go anyway because he felt fans would become the troll themselves and laugh with the character, but it backfired because none of the players got the idea that he was joking with the making of the character itself so there were complaints on the character. My reasoning is the character's terrible VA and creativity behind it (which is merely an opinion of mine.) the other reasons for the other players is the amount of time and effort he tried to put into it with some of the complaints actually being genuine, would you believe that? actually genuine. Which to my surprise because most Tekken complaints are merely idiotic to an extent. Few of the idiotic ones was removing Lucky Chloe or turning her into a robot, which is typical from Tekken players to ask because there are obviously bears and robots while hearing those complaints in a cringeful way, however most of the sane ones generally have a natural say to go with "Meh, she's in the game..but was hoping for something more." Which is a general natural response from sane players/buyers while still being reasonable on the matter.
You ever saw Powerpuff girls? Sugar (Buyers), Spice (Tekken), and the last ingredient (Everything nice) is that he threw himself in there which was perfect and touche plan to troll but with an incredible side effect that is incredibly negative with some feedback that were actually reasonably negative towards the character itself while the others being mostly insane.