For me anyway - and of course I can’t really talk about this without spoilers.
The third movie is broken in to three fairly distinct sections.
The opening bit where Morpheus and Trinity Rescue Neo from The Merovingian, take him to meet the Oracle and get confirmation of Agent Smith’s growing power and danger - this section ends with Trinity and Neo taking off for the Source, and the rest of the cast going down to Zion.
The Middle Bit is around 40 minutes long, but seems longer, and concerns the defense of Zion, showing what Morpheus, the Kid, Captain Mifune, and others are doing to defend Zion. This sequence ends with assuance that they will all die soon unless Neo does his thing.
Then the closing bit, with Neo and Trinity making it to the source, Trinity dying, Neo facing down Mr. Smith and the conclusion.
The key problem is that when you think about it they spend 40 minutes of the movie on the Defense of Zion - which they pretty specifically tell us is a lost cause. Zion is doomed unless Neo can save them. So no matter how valiantly Captain Mifune dies or the Kid rises to the occasion, it is all irrelevant to the over arching story. It just fills time. And since i found the action in this sequence dull and since it focuses on some of the less compelling characters, it just ruins the pace of the movie for me.
When we get back to Neo my attitude isn’t “Gosh I hope Neo can save all those heroic people.” My attitude is “Thank Goodness we are back to the storyline that actually matters and is interesting.”
Contrast it to Return of the Jedi or The Phantom Menace. Both end with a similar structure where you have a space battle, a land battle, and a personal battle by our main hero (or Heroes). Here in the Matrix Revolutions you have a land/space battle and a personal battle by neo. But in both the Phantom Menace and Return of the Jedi you clearly know why all three battles matter you are invested in all three. In Matrix Revolutions we are shown two battles, one of which matters and one of which ultimately doesn’t.
Anyway just my two cents - I should say I really liked Reloaded (and the first third of Revolutions for that matter) as a great second act. I think had they cut back the invasion of Zion, made what was happening in the third bit a little more explicit, than it would have been seen in a better light.
