I'm someone who likes to explore her vulnerable, insecure side, and people don't like when I do that, because I turn her into a real complex woman instead of a perfect one-dimensional Mary Sue cipher.No, people don't like your Kaho because you regress and warp her character into something that's not recognizable as coming from CCS, much less being Kaho. And your "wahhh I love Touya but our relationship isn't perfect bliss so my life SUCKS!!!" characterization is just as one-note as anything you're bashing. At least manga!Kaho moved on and had fun instead of dwelling in misery.
It's not like there isn't room for complexity and angst for Kaho in canon. What about her place in Clow's plan, and how it ruled her life for a long time? There's plenty of opportunity there, and oh look, it even has built-in Touya angst. If you hate that Kaho's a "Mary Sue cipher", then why do you base your characterization on the version that's more Sueish, more of a mystery, and with less reason and explanation?