The Acting
Say what you will about Charlton Heston's politics, the man was a fine actor on occasion, with a steel-jawed determination and fury that no amount of monkey beatings can dull. Sure, his love interest, Nova, was played by the studio head's girlfriend, but the apes were all talented actors (Roddy McDowell, Kim Hunter) under that latex. The remake, on the other hand, had us follow a dazed Mark Wahlberg and his comatose love interest Estella Warren as our protagonists, a grave error that even Tim Roth could not remedy with his fine monkey acting. Even if talented thespians were cast in this planned prequel, there will never be another Heston, so why bother?

The Makeup
The makeup effects in the original Apes were so amazing for their time that the film's makeup artist, John Chambers, was given an honorable award at the 1968 Academy Awards. Granted, that was over 40 years ago, and while the makeup may not have been the most realistic, it was believable, because the apes of that film were not real apes -- they were apes who had evolved to be like men. They walked like men and talked like men, so their faces were more human, and it contributed to the overall visual impact of the movie. For the 2001 version, Rick Baker made the apes look even more like real apes, but that didn't make Michael Clarke Duncan any more believable as a gorilla warrior, or make the film's message of tolerance and acceptance any more true.

The Movements
In the remake, the monkeys move and ride like men most of the time, but when they run or fight, they move like monkeys. Why not have them run on two legs, rather than loping across the desert on all fours? It was this difference, combined with the more animalistic makeup, that made the apes seem both more familiar and less threatening. Monkey strength or no monkey strength, it's not as scary to watch Mark Wahlberg fighting what look like actual monkeys in clothing. That'd like fighting Lancelot Link, Secret Chimp.

Sexy Apes
In both versions of the film, the main human character shares a kiss with a female ape. But while the original film had the female ape dressed in similarly shapeless clothing to the male apes, with similar features and a loving relationship with a male ape, the remake gave her a pantsuit, a Rachel haircut and put her in a love triangle with Mark Wahlberg. A message about equality among species is one thing, but there's something about the sexualization of Helena Bonham-Chimpanzee and her technicolor dreamcoat that makes us uncomfortable.

The Ending
The ending of the original Apes is one of the most famous, most parodied final scenes of all time. While Burton's remake varies from the original in many ways, Burton actually went back to the source novel to create a totally new final scene in an attempt to surprise the audience. Unfortunately, despite the fact that it had plenty of shock value and could have set up an intriguing (or ridiculous) sequel, it still came as a disappointment to people who knew and loved the original ending. So our choices are "ending we already know and love and have seen a million times before" and "new ending that has no chance of being anywhere near as good"? What's the point?