RE: Biggest flaw is that it did not mandate the return of all Mexicans in the U.s. back to Mexico
How could this deal be made if we DEMANDED this as a condition?
Do it through commerce. Both nations agree to stop all illegal commerce and financial transactions, especially the results of illegal activity. The US would be bound to stop all private remittances from Mexicans in the US to Mexico. We should anyway. Unless they can prove that they were legally authorized to work, that US taxes were paid, the monies should be seized. Further, why not provision commerce to include credits or something for repatriated Mexicans. Make it in Mexico's interest to bring these workers and families home.
No, this "deal" is simply an open-borders, cheap-labor-express, chamber of commerce loved give away. Americans lose with this new NAFTA. Better to end NAFTA than swap it with the same thing.