Absolutely not with Class A drugs.
Stuff like weed, yeah whatever. I'd love for it to be legalised. Even some Class B stuff too, whatever.
But Class A drugs can so easily be misused. So, so easily. You just can't trust the general public to be safe with this stuff. Especially here in the UK. People can't even be trusted to drink responsibly. Introducing heavy-duty stimulants, opiates, psychedelics, cocaine etc to the general public is not going to go well. People are going to abuse that shit. People are going to go out in public on that shit. People are going to try and drive on that shit. People are going to combine their drug use into a death cocktail (especially with good old booze involved in the decision making process)
Yeah it's possible to be safe and responsible on these drugs. Easily in fact if you know what you're doing. But you can't trust people to do that on a large scale, and that's why I can't support the stronger stuff being made more readily available.
It's not too difficult to get hold of Class A stuff these days but it still requires some effort and knowhow to some extent, which restricts the potential for irresponsible use to a very small number compared to what it could be.
Crime wouldn't go down massively with drug control. Gangs would just move on to something else.