I can certainly understand your point, and in some respects I agree with it. I really liked the story in TSL and I feel like it receives some undue criticism.
However, I see some value in TSLRP, in that the author (Avellone, I think) has made it clear that a lot of the content he wanted to include just couldn't be done because of the time constraints. That led to some cut content that would have helped fill some holes that exist in the storyline.
At the very least I am intrigued to see how TSLRP ends up. It might change too much and a lot of people might end up agreeing with you. I applaud the effort nonetheless, however.