I seriously hope the family keeps the lock on the rights. Current generations should gain love of Tolkien through his words, not the Hollywood bastardizations of his stories. As great as the original trilogy is as an adaptation, it is NOT the same as the book, and, either by necessity or poetic license, does omit/change details. As for The Hobbit, forget it. Like John said, as a Tolkien-based piece I can watch and enjoy, sort of, bit it's a blatant departure from almost the entire story, with major plot and thematic changes.
There were only a few changes about the original trilogy that irked me. I was ok with the absence of the Borrow-wights, Old Man Willow, and TB. Without the written word, it would have taken too much exposition to explain them to the lay audience.
The swap of Glorfindel with Arwen didn't bother me much, but I have to say the overall reliance on Arwen's diminishing and their love as a plot device was a bit much.
Totally agreed about Frodo's character. He was not the whiny pissant be was portrayed as, and the "love" between him and Sam was actually one born of tremendous respect and loyalty, but the on-screen portrayal bordered on romance.
Probably the most egregious change for me was Faramir's character. He is completely benevolent in the book, while his initial antagonism in the movie not only warps him at first, but also results in an unnecessary confrontation at Osgilliath whereby Sam has to once again prevent Frodo from being a pathetic loser by giving up. Only then does the cinematic Faramir see the forest for the trees, and I still don't see why that conflict was necessary.
Those are relatively minor gripes, in my opinion, compared to the slutjob done to the Hobbit, though.