Woah. If that's true, that was a huge blunder. I feel that the overall quality of the manga dropped after L died. That part was like the climax of the entire manga.
Not to say that the parts after L's death were bad - there were quite a few good bits, but on the whole I enjoyed it a lot less and only read it to complete the story.
I wouldn't have minded if the story was wrapped up nicely after L's death.