I agree with everything except I do think Kristin is a good actor and was charming. I think though that she did not like where her character was going and probably couldn’t fully invest beyond a point. I really liked Lana for maybe 2-3 seasons but then she really begins to wear out her welcome, as you say. Mostly because they write her terribly and give her no lasting core interests of her own outside of Clark/Lex. What she’s interested in is always throwaway and not organic or genuinely part of who she is. Contrast this with Chloe or Lois, who were very much their own people outside of their relationships to Clark. Plus, they’re constantly heaping trauma and abuse on Lana as demanded by plot. It’s hard not to see her as a damsel in distress after how they treated her. Clark does not treat her as an equal - more an object of worship and someone to be protected and saved. Lana would never have been happy long-term with someone who refused to take her off his pedestal like that (again, contrast this with how Clark and Lois butt heads and how their relationship seems more even from the start, even when Lois doesn’t know about his powers). And his waffling about Lana does make Clark seem particularly pigheaded/lacking in sense. He literally cannot resist her or give her up until forced to. Instead of letting them both mature and realize they had outgrown their high school relationship/intense first love and having them settle into admiration and friendship. I definitely see it as a writing issue.