Even though that is my own opinion, I have read the books for numbers VII VIII and IX when I was a kid. And holy crap, these were boring as hell. They are absolutely not worth doing a sequel. One of them, I think VIII, was unbelievably long and boring it's insane, and I hated that the big bad guy is Palpatine v2. Terrible books, I regretted reading them and spending so much time on those (it was before the prelogy came out). I thought this news about Disney was a joke. In a way, I'm hoping that if it's true, maybe the total change it may create would be of benefits for the franchise.
The problem with star wars I II III for me is that so much feels like made up around the original trilogy. I haven't been able to "get" the prequel, I still enjoy it as in "it's still a star wars movie" and I love the universe of the whole franchise, but I have never actually enjoyed the first 3 movies as masterpieces. They feel like yet another hollywood movie post 2000-ish, ie way too much CGI, they feel like in 10 years they will already feel like old (while the original series still feels ok except maybe IV because the budget was lacking at first). There are way too many explosive action scenes that last 10mn, way too much politics as stated AD Chaos, and I'm pretty sure 99% of people (me the first) just have never actually understood most of the story, because the complexity of the politics affair in the trilogy is over the top and could be simplified and still be "deep", way too much imo compared to the original trilogy. The difference is ridiculous and inappropriate imo. To me it feels like a complex of "let's make it complicated so that we can make people think it's so-deep while in fact we have simply drown them under over information". Also I totally agree with the video posted before, the trilogy lacks basic qualities, the very first one being there is no main character to follow, and the absolute lack of personality the characters have (except Jarjar but was he really necessary in the script ? feels like a clown to entertain the kids). They are really, really good for entertainment, way more than the prequel in a way, but they lack way too much to be "masterpieces". I'm not sure people will look at them in 40 years like we look at the prequel now. The simple fact most people have a problem with them is a clue, since it's a very popular franchise. The number argument is indeed fallacious, but that has never been the case with the original 3. Too much of the prequel feels artificial, too much was put into CGI and too little attention was paid to the actual characters and the intensity and symbol of scenes (in a nutshel : to cinema as an art)
I really enjoyed the end of the prequel though (the last hour of so of III), and I just realized why : it has a real purpose, which is explaining the "rise" of vader and create a true transition with IV and serves the purpose of the supposedly point of I II III (explaining IV V VI). In between I and III, there is so much it feels like artificial and if the whole story was changed completely, it could have worked as well which just makes me feel like anything would have worked since so little is said in the original series about where they come from), and my last feeling when I get to the end of the prequel is that "okay now we're getting somewhere at least".
To me I II III don't feel so deep, but more overly complex, and yes you will find a lot of information there, but does it make it "deep" ? You can create bridges between the movies, which is cool I admit, and I like playing "where is waldo" in a way with pieces of movies, but I wouldn't say it's a reason to consider the prequel "deep". It really reminds me of series Z sci fi movies which are most of the time incredibly complicated in their storyline.
@J the Tyrant : nothing wrong with Last of the Mohicans. What a wonderful movie, and especially, what a tremendous-epic-incredible-orgasmic last scene
EDIT : something I enjoy though, to be the devil's advocate, is how the design of the I II III weapons, suits, shuttles, cruisers, fighters, relate to a future empire. You can feel something is going on just by putting the designs in perspective with the empire from IV V VI, which I found very subtle in some cases. And the further you go, the closer they get to Empire-like designs. A lot of care has been taken of symbols and implicit clues to create a relationship between the prequel and the trilogy, what I find lacking is how the movie themselves were directed, acted, and scripted.