Total Film has an interesting opinion piece/feature online where they have twelve things that should have been kept in the Harry Potter films.  Here are a few, the rest are at the link!  I agree with every single one, especially the following few:

Peeves The Poltergeist: Pesky prankster Peeves is an anarchic poltergeist whose only goal is to create chaos. His sworn enemy is Argus Filch, the school caretaker, who has to clear up after him. Rumours that he could be the ghost of Jeremy Beadle remain unfounded. Rik Mayall did film a scene as Peeves for Philosopher’s Stone, but it got chopped.

The Origins Of The Marauder’s Map: If you’ve never read the book, the magic map given to Harry in Prisoner Of Azkaban seems to have ‘lazy plot device’ written all over it. In fact, what it actually had written all over it is ‘Messrs Mooney, Wormtail, Padfoot and Prongs’, which is a clue as to its origins and a whole subplot about Harry’s dad, Sirius Black and the other map creators being animagii – those with the ability to turn into animals.

Kreacher’s Hoarding: Aged house elf Kreacher would have been a no-brainer to cut from the fifth film, but JK Rowling herself insisted on his appearance. But his role was snipped to a virtual cameo, wandering around the Order Of The Phoenix’s HQ (Sirius Black’s family home) grumbling and cursing. In the book, the sour creature has a major role to play in betraying Sirius to the Malfoys. A big plot point about him hoarding old Black family heirlooms was left out, but will have to be addressed at some point in the film series….

Thanks TLC!