I use a terminal app called Trim-app.
You install the .exe file in usr/bin
then type:
$trim-app -a i386 (return)
This gets rid of ALL binary except Intel
$trim-app -a PPC (return)
gets rid of all the i386 code
ML used to cause problems apps would not work properly
and the console would say, (after using ML)
"x/x/x2 not found. DID find x/x/x2 Mach-O but wrong architecture"
Using trim app Ive had no problems.

Plus ML still leaves from a few to many dozens of lproj files behind-you can find and remove them using an app called Easyfind-I dont use Spotlight, ever-but that kind of defeats the purpose of ML...