Drugs come with a trade off. It means you don't have to take drugs to compete.
On paper yes , but it really isn't true.
Mix up enough drugs on certain builds and you almost only get benefits. Psycho , buffout , jet , nuka , cigs = 2 ap + 1 str + 3 end , -1 pe , charisma penalty is useless for " ugly powerbuilds " you know there is a limit on how ugly can you get or jet , nuka , cigs on a 1 str powerbuild = 2 ap , 1 pe , 1 agi , then there is jet , nuka , cigs , buffout that is awesome on builds that requires str and DR loss is not very important , for example sneaker or lazer rifle sniper, 2 ap , 1 pe , 1 agi , 2 end - 15% DR. Hell Cha drugs are used on merc leaders to save up 3 points mentants and beer when buying merceneries.
Well there are other good variations but you get the point , it gives advantage and builds without drugs have a disadvantage therefore cannot compete as good.
So in the end it is a viable option to make a drug that gives these attributes with " fucked up " withdraw penalties balancing out that you don't need to eat 5 drugs in order to get this advantage 2 ap + 1 str + 3 end , -1 pe or any of those other attribute variants.
Make some multiple drugs like these , make it not possible to take 2 or multiple at the same time(some overdose mechanism) and voila you get new drug system that makes sense and ugly powerbuilds don't have to chew multiple drugs like candy to get something out of it.