Undoubtedly, Christians will hail Fireproof as a great triumph for Christian filmmaking: a glossy looking "blockbuster" of their very own.
As a God-fearing gent myself, I found Fireproof every bit as corny and mediocre as you did (give or take a few points on the scales of justice). And, anecdotally, pretty much everyone else I've talked to who are spiritually like-minded weren't exactly proclaiming Kirk Cameron's name for Oscar contention. I know there is certainly a healthy contingent of Believers that think the movie is the cat's pajamas, but be assured, we are actively praying for them.
Anyway, good review, and I agree with your take, but no need to generalize--Jesus may be our homeboy, but He didn't purge us all of our cinematic sensibilities (though my love for Gymkata and Saved by the Bell: Hawaiian Style do little to bolster that sentiment).