Morinaga to me has gotten better at things like composition and backgrounds. Her characters have gotten a little bit more personality, but they're still pretty flat considering she has multiple chapters to show them to the viewers. I know every story has already been told (that's why tvtropes exists!), but I get the same feeling with her as I do with Joss Whedon nowadays.
Joss Whedon was praised years back for many out of the box choices he made in his shows, but nowadays he's been getting more and more criticism for not growing and changing with the times. What he was praised for with Buffy 20 years ago no longer gets praise, and he seems completely baffled that what worked for him before no longer gets him the praise he used to.
Morinaga is similar. When A Sigh a Kiss and Cherry Blossom Pink came out, it was super popular. It was angsty, and it had a ~*YURI*~ misunderstanding, and it ended cute and fluffy. It came out in the early/mid 2000s and back then angst was THE THING. It came out just before the My HiME and Kannazuki no Miko animes. But as an author, Morinaga hasn't grown when it comes to the stories themselves. Her stories still follow the same tired tropes, and she hasn't branched out and shown us she's capable of anything different in her multiple chapter works. It's like we the viewers are stuck in a loop, and Morinaga can't change with the times and make a story that doesn't rely on the exact tropes she used in her previous famous works. I absolutely LOVED Girlfriends and think with a bit of tweaking story-wise it would have made a decent 12 episode anime around 2007, but now if they made it it would be too late because it's no longer innovative. Everything she's made since Girlfriends has really fallen flat because it's just the same story with different characters.
Exactly!
Morinaga's writing isn't what I'd call terrible but is very by the numbers and safe. Either she hasn't realized that sensibilities have changed and Yuri has matured enough as genre to allow new and different approaches to it, or she is trying to make lighting strike twice and repeat the success that she found with Girlfriends. In way, she has become the mangaka equivalent of a one hit wonder.
Ironically, I think shown the most creativity and willingness to try new things when she made the wonderful mindfuck that is Mare
I'm not saying she should stop writing. But if she doesn't start branching out and exploring other yuri plot possibilities, she's never going to stand out from the vast swaths of yuri managaka competitors coming out today. Sure there will always be newbies to yuri who find her writing style cute, new, and relatable, but she's going to be relying on newbies her entire career at this rate and that's not a very sustainable fanbase to rely on. I'll glance at her new stuff that comes out, but I'm not going to get my hopes up anymore. I'm tired of waiting for something new.
The way Hina and Hana was cancelled midways while her other recent stories have been short lived is proof enough she can't rely on her reputation much longer. She needs to shake things up, and to explore the possibilities current Yuri offers if she wants to remain active on the yuri scene.