A designer drug could give the pleasure of alcohol without some of the damage.

This new drug might be less addictive than alcohol, but that's not automatic. Addiction results from the body's physiological adaptation to the effects of the drug. Whichever receptors respond to the new drug as they do to alcohol, they would tend to adapt and produce addiction. Meanwhile, whichever body systems are not affected by the new drug would not develop addiction; that might reduce the total addictive effect, but how much that occurs would have to be seen.