1. Allow local police as well as federal police to pursue drug-related crime. This is a strengthening of anti-drug laws.
2. Codify the specifics for amounts of drugs which, if possessed, do not result in criminal prosecution, but diversion to treatment programs. Currently, this is at the judge's discretion, requires some kind of evidence of being an addict, and is apparently a source of corruption (pay a bribe, get the charges dropped). This change seems to be relatively neutral.
It doesn't appear to me likely that these changes would have much effect on the availability or acceptability of illegal drugs in Mexico.