The seemingly small but fatal mistake of NOES 2010 *major spoilers*
Freddy's change from child murderer to child molester. This alone ruins the film in a few ways...(from here on, I'll take a cue from Phelous and only refer to the original as "Freddy". Remake Krueger is now "Teddy")
1- Freddy was something of an "anti-hero", just like his fellow slashers. Teddy can't be because he's a child molester.
Is it weird that child molester is worse than child murderer and that we can easily accept the latter in a villain, but not so much the former? Maybe. And it certainly isn't an attitude that carries over to real life. But regardless, it's true in the case of Freddy. The creators of the original understood that and removed a scene that revealed he molested the kids he murdered. A couple of the sequels would vaguely hint at this aspect of Freddy, but nothing that flew directly in the face of anyone who saw him as "only" a serial killer.
2-The motive has changed, And Teddy's isn't one you can get behind. So again, no anti-hero status for Teddy.
In the original, Freddy wasn't after the teens per se (not until later in the series anyhow), he killed them as a way to get revenge on their parents, who had formed a vigilante mob after Freddy's release, burning him alive in his hide-out...an abandoned boiler room. This happens to Teddy as well but it ends up a fairly insignificant detail that really could've been replaced with any scenario, so long as it resulted in Teddy's death. That's because Teddy's motivation isn't getting revenge on his killers, it's getting revenge on the kids. Because they told on him. For molesting them.
In the original, you could make the argument that morally, the parents crossed a line, however understandable it may be. That, and the hideous manner that Freddy was killed, made it easy to see why Freddy at least believes he has motive. With Teddy, the motive is so direct that even he (especially in death) should see that he is the only villain here. And since there is no question of morality when it comes to the kids telling on their abuser, we can't see why he thinks he has a motive.
3- The glove. It doesn't even make sense now.
The glove was the "holy shit" aspect of the original movie. Freddy wouldn't have had a chance of gaining popularity without it. And its genesis was simple...he killed with it.
Teddy on the other hand...why does he have this glove? He wasn't a killer and it hardly seems like a useful gardening tool (except for making hedge angels, of course). He uses it...somewhat, but the movie never gives him a plausible reason to have ever made "finger-knives". If lightly scratching the kids was his...thing, then that's a hell of an over-complicated and unnecessary item to accomplish it. It's almost like he knew he would be a supernatural killer after death and decided to make a toy for himself ahead of time.
This could've been fixed...mostly. If they had just went in the direction they hinted at...that Teddy was innocent, it would've made a huge difference. It still wouldn't explain the glove, but with Teddy a sympathetic character who had an understandable motive...I might have never even noticed that the glove didn't make sense.