I felt the opposite, there's a lot of Takemiya's work featuring a insecure girl with an assertive one
It was kinda nice, i guess, but i honestly think she stays in her comfort zone a little too much
Nothing wrong with becoming incredible at one style. Blacksmiths had to iron out over one thousand swords before their work was good enough for them to be considered recommended for even low infantrymen (thankfully the life of a mangaka is a bit more cost effective than that).
What she does change is the plot, the flow, the outcome, the feel of each story. Her previously scanlated oneshot was an angst-filled 'reality slaps you in the face' style while this was, although not a polar opposite, completely different in its own right.
Besides it can be a good thing to be a "go to" for something. Like if she does only stick to her typical insecure-assertive style matchups, then whenever I want to read something like that I'll turn to her. If I want to read something of a different nature, I'll read someone else who's better at it. She's been spending her training efforts on her art style, since it came across as a bit underdeveloped and sloppy at times in her earlier works. It's come a long ways.
And to be honest, and this is a more personal thing, I like Takemiya for her master of plot control. I've been hard-pressed to find a story that I didn't love.