Revealing mistake: When Jason is whacking the party goers, you can see the padding Jason slices under their shirts.
Revealing mistake: When Jason cuts off Freddy's arm you can see the actor has his arm tucked behind him under his sweater.
Revealing mistake: When Jason swings his machete at Blake on the porch, as he swings you can see the actor stop swinging so it doesn't even make contact with Blake at all.
Answer: This is one of those questions where we'll probably never know the real reason because different people involved have different stories as to why Kirzinger was picked over Holder. Holder himself has said he doesn't know why he didn't reprise the role, especially since he was told he would and was given a script. Some accounts say Yu wanted Jason to tower over Freddy and Kirzinger is 2" taller than Holder. One of the casting directors said Yu thought Holder's version of Jason was too campy. Meanwhile, Yu said it was New Line Cinema's decision to recast Holder because they want to change the direction of the film and used this film as a reboot of the series.
Bishop73