First, the Hunger Games points you bring up are very valid, though I completely fail to share your views on the setting for the Games. The forest was very unremarkable in that it was just like any other forest, but it seemed like a cool place to play paintball, which is basically what you want out of a battle-to-the-death. I think the shaky-cam stuff was 1000x more detrimental to what was an otherwise good film. Beyond that, your point is utterly dead-on – faithfulness to the source material, coupled with some bad directorial decisions and some cheapy visual effects all combined to make what could have been great merely good instead.

Second, on the TMNT thing, I think you guys are just grasping. No, I don't really get the "fantrum" around that – it's clearly a typical internet overreaction and folks should just chill. I'm not even really a TMNT fan, but I have to say that, to me, the idea of making them aliens is just so damned absurd that there is no way I can give it the benefit of the doubt. If it were someone like Nolan, that MIGHT not be such a tall order – he's made a career out of doing things seemingly way out off base, then pulling it off like a genious (for instance, your example of Ledger as the Joker). But, since this is a Michael Bay production, there is no chance in hell you're ever going to get me to give that guy the benefit of the doubt. Simply BECAUSE it's Bay, it sounds like a terrible idea, not because of the idea itself. So, really, I think this particual example is worthless as support for your argument (which, I might add, I DO agree with overall).

Third, while your Harry Potter example is pretty much true, I have to play devil's advocate here and say that it's easily more the source material's fault than the directors for the first two films – you talk about how Cuaron's thrid entry was when the franchise started to be good, and I agree with that statement 100% – however, I felt exactly the same way about the books. I almost quit reading after the first two, as they were just a tad to silly and childish to really grab me, but after seeing the third MOVIE, I picked up the third book… and the jump in quality you see between Movie 2 and Movie 3 is mirrored in the books – the third one was when I actually started to REALLY enjoy the series. So yeah, I do think Cuaron made a better film than Columbus ever could have, but he was also working with much better souce material than Columbus ever had! While this does not invalidate your point at all, I feel it's important to note that the director having the guts to stray from the source material was far from the ONLY reason the third movie was so much better…

But, as I said, I do agree with you for the most part, that in most cases, that a rigidly slavish approach to adaptations can do more harm than good, especially with movies.

On the other hand, it's a TV show, not a movie, but Game of Thrones is remarkably faithful to it's source material, and it's been amazing… maybe it's just the medium, but sometimes the source material is just good enough that tampering can only make it worse….

Hmmm… yes. Christ, why is it so diffcult to understand when the word "Mutant" is in the title. I'm all for taking creative liberties but changing the fundamental aspects of what makes franchise intriguing is something else entirely. If someone can't do something new and different with source material without changing everything then they probably shouldn't do it.

Oh and choosing actors that wouldn't be the fans first choice is NOT the same as changing the origin of their title characters.

To use your example, changing the turtles to aliens ends up leaving them as neither mutant nor ninja nor turtles (and possibly not even teenage, depending on how aliens measure age). By that point it's unclear what the point of linking it to the earlier property at all is supposed to be, other than brand recognition.