Are the current regulations causing problems then?
Has anyone turned up for work having stayed within the current rules and still had >0.2 mg of alcohol in their blood? I seriously doubt it.
If any problem does exist, it would be amongst those who already break the current rules - more stringent rules would make no difference.
In fact, a 24-hour rule is likely to be broken far more often. For example, an evening call for an aeromed the following morning may induce a crew member and his/her exec to ignore that glass of wine consumed with dinner. Both parties know that it would be undetectable the following day and would consider it ridiculous to refuse a task in such circumstances. They wouldn't receive much support from on high for applying the regulations to the letter, and "lack-of-flexibility" would be cited by those affected.
The absence of sensible regulation would result in reliance on self-policing balanced against the importance of the task.