»If Smith didn't exist...«

Has anyone ever thought about what the consequences would've been if Smith hadn't existed in this version of the Matrix?

Neo chose the door to the left. According to the Architect, this would've led to the destruction of the Matrix. In M3, if Neo had no excuse to go back to the Source (like destroying Smith), the machines would not have stopped their attack on Zion. This would effectively have put an end to the human race and brought the machines down to a barely survivable level.

Smith would then have taken over 01.

Therefore, Smith is a blessing in disguise! Smith is the reason that Neo returns to the Source at the end of Revolutions and completes the cycle. Smith is the reason there is a truce between the machines and humans, and Smith is the reason Zion is saved. Without Smith, Neo's purpose would have ended with his choosing the door to the left. Ironic, no?

Hey, cool idea.

Or maybe Smith is the reason the cycles as they were going, had to be changed.

The relevant issue was whether or not the two "sides" could come together and stop the pointless war.

Take this scenario:
Smith becomes more and more rogue.
Oracle guides Neo in different direction than predecessors. Or was it the Source (or providence)?
Neo could be motivated to deal with Smith (to save Zion)
Deus Ex Machina could be motivated to spare Zion (to deal with Smith)
As Merovingian said to make a deal each one must have something the other wants. "It is of course, the way of all sings."

"IT IS DONE."

roll credits

But what about the rest on both sides? What will they do?
...to be continued - Enter MxO

So you could say "thanks for common enemy, Smith reuniting man and machine" or you could say, "thank goodness that at least one on both sides were wise enough to unite against the common threat that they created by the feud in the first place."