Carrey was perfect in the skit. For the movie? Well, it made sense just having Farrell and Kattan. This silly but fun movie is alright (the original skit was funnier), but Carrey had much better things to do.
You want something corny? You got it!

Conflicts with the Turman Show and they didn't want any former hosts.

Apparently he helped with the script, and Chazz Palminteri's character sees Jim at one point offscreen if you recall. It would have been cool for him to actually pop up in the movie though. He was a busy man at the time, I'm sure.