The revelation of the enemy is a big letdown in GFIII.

In the first 2 movies, the Don deduces who the hidden enemy is via intuition and a series of ambiguous clues that we discuss here on a daily basis.

In GFIII, it's more like:

Michael: Who's our enemy?

Tomassino: Don Lucchese

Michael: OK, let's stab him with his eyeglasses.

Not quite as deep or memorable.

"A man in my position cannot afford to be made to look ridiculous!"