I really liked the way you handled this, as well.
To me, Clark's biggest mistake in the BatP/HoL arc was letting his feelings get in the way of the situation at hand. Clark confessed his love, which I think is perfectly understandable under normal circumstances. In this one, however, getting close to the story was not smart in the first place, because it took away his credibility in warning Lois about Lex.
This was the conversation they should have had before they found out Lex had bought the planet. I like that Clark took it sensibly, trying his first tactic without bringing up the "Lex is evil" scenario. All Clark's accusation did was make Lois defensive, and rightly so. It made it sound like Clark was just saying those things because he didn't like Lex, whether or not he believed them. Tack on the hurt and you've got a discredited Clark.
If all he could do was slam insults on Luthor, how could she trust him to not be biased in helping her? He was supportive and logical in the way he went about things. He wanted to get her away from Lex, but he wanted to support her, too. This was a good middle ground.
I see this as the what Lois would have done if everything hadn't fallen apart. To me, her breakdown in the series was very in-character. 1st season Lois is ruled by her insecurities. The planet was her stability; her home. That was taken from under her, she was losing Clark already, Perry and Jimmy left, and she was rejected by Superman. She didn't have anything to cling to. Someone as insecure as Lois (the Rival, anyone?) could easily make an out of character decision when her support system is pulled out from underneath her. I liked the way they handled it on the show, but I love your interpretation of what might have been, as well.
The other thing I love is that Clark acknowledges Lois's feelings for Superman as being understandable. So many people get on Lois for that, but Clark's mannerisms are completely different as Superman. He's a different person entirely.
