The key difference, for me, is that Greg wasn't on the story team in 2001/2002. He was given the job to write the comic at the last minute in 2001 when he showed up whoever it was they had writing it originally, and his role grew from there.
I try not to put my dislike of anything about BIONICLE post-2003 on Greg, because I realize that he was only a part of it. Even if he wasn't there, I wouldn't be super happy with the direction and aesthetic BIONICLE assumed over time. I guess what I was trying to express in my last post was that I was glad it looked as if Greg wouldn't be writing any of the final story material. His writing style is definitely not to my tastes, for one reason or another, so for me it is encouraging to see that it would appear new people will be in charge of the books/comics/show/whatever media the theme will be conveyed in. That's just a subjective thing, though, I know lots of people will be sad to see Greg's role reduced.
As for your second question, I'm just not personally engaged by the type of story that BIONICLE eventually became. It was a little too serious and intense and sci-fi for me. I prefered the freer, less defined, flowery style that was present at first. Again, that's just me, really.