Lots.
Lots of things could have upset the apple cart.
What resulted was a stellar film that, in a perfect would, would be worthy of some Oscars (we know Hollywood doesn't like to reward horror often however) .. If these few elements would have been included, perhaps the movie's successful script would never have made it to cinemas..
MOVIEPILOT has a bit more on the items that floated from the script into oblivion. Read with caution.
Concerning the MOST controversial of all (and there are a LOT), this:
Lost in the sewers and with nowhere to turn, Beverley realizes that the only way for the group to escape is for each boy to take it in turns and put their "thing" inside of her. By losing their virginity together, the Losers' Club can then once more tap into the power of the Turtle and find their way to safety. Yes, this scene is even more insane than the Deadlights themselves, no Muschietti didn't include it in his adaptation and yes, Stephen King himself continues to defend the sequence, even now.
Whether you believe that the sewer gang-bang should have appeared in the movie or not, it's fascinating to see how Muschietti tried to remain faithful to #IT while still navigating the controversy of #StephenKing's original text. It's no wonder then that Cary Fukunaga's original script never made it into production. After all, there's only so many controversial plot points one can add to a movie before the inevitable starfish attacks and incestuous rapes take things a step too far.
The HORROR REPORT ponders if these omissions are such a bad thing. After all, the film was WILDLY successful and will most likely continue to be throughout at least the early autumn.. Ignoring some of these aspects of the book, even with Stephen King adamantly defending them, may have been the best decision ever made.. mainstream for the masses! The Loser's Club wins.