The main problem is Morgan... Cast someone else, this might be OK.
OK, the script isn't the best, but you have a great soundtrack and Willis doing his thing. Morgan just doesn't know when to play subtle and when to let loose. He's a screaming banshee for the lions share of his supposedly comedic moments in the movie. A contender for his funniest moment is when he's dressed as a mobile phone, and that has nothing to do with mannerisms, that's just costuming.
I would rather have seen Martin Lawrence partner Willis, and even that is erring a bit on the low budget side... At least he has experience of crackling cop chemistry, with Will Smith on the Bad Boys franchise. Morgan is like a man desperately trying to swim, but drowning nevertheless.
If you're looking for a parody of buddy movie cliches, try "The Other Guys"...
This is where the magic happens... and by "magic", I mean nothing.