Danny is a Troper today.Think about it. At the age of nine, he's already Genre Savvy enough to hang up proverbial lampshades by the dozen. Then he goes through an adventure that's more Troperiffic than any movie he has seen so far which is impressive considering how Troperiffic the Jack Slater movies have already been until then. Now imagine him today, some 30 years old, and most likely a movie addict.
The Last Action Hero doesn't parody only action films...The scenes set in the "real world" are actually a clever satire of Film Noir. Consider- it's almost always night and it constantly rains. The movie theater is falling apart and appears to have its doors ripped from some Gothic keep. Criminals are able to kill openly in the streets and the police never arrive. The villain manages to outwit the hero and shoot him in their final confrontation. No one even cares that Death himself walks the streets, because Danny has simply jumped from one genre pastiche to another!
Related to the previous theory: there is no "realest" world at all.Slater believes his world is real. So does Danny. It's possible that both universes are Mutually Fictional, with Slater living in an action movie universe and Danny in a film noir universe. There is no universe that's "more real" than the others — they simply work by different laws of fiction.
Benedict's plan to bring together all the villains would have failed.Why? Who the hell is this guy to them? Why would any of them follow that guy? Why would they believe him? How could he keep them under control? And why wouldn't some of them just eat him?
Tom Noonan gets arrested for murdering his agent.He shows up in full Ripper regalia, acting all killer-y. Then, his agent is found dead from an axe wound. Any witness would say, "last time I saw him, he was walking to a secluded area with Tom." Mr. Noonan is royally screwed. He does have hope, though. He was seen showing up at the premier a few minutes later as himself (I think even with his wife). This would lend plenty of credence to an argument that the Ripper was some sick imposter. Hell, eventually someone's going to check up on the downed power lines on the roof and find the Ripper's body. How the world will react when it becomes known that this deranged lunatic has the same finger prints, dental records, and DNA as famed character actor Tom Noonan is not known. To put it simply, Tom's got some bad times ahead.