We have plenty 'safe' GABA-A agonist, the issue is alcohol's greatest risk and greatest hard is dependence. The health effects in non-addiction scenarios are not related to its function as a GABA-A agonist but rather the specific metabolism of ethanol produces toxic metabolites.

The withdrawal from any type of GABA antagonist/PAM type drug can be lethal. The acute and long term side effects of ethanol discourage abuse.

Also acute overdoses of the safe benzo/Z-drugs are strange & alarming since you can put yourself into a 24-48 hour coma but recover pretty quickly.