Unrelated, but anecdotally whenever I hear someone going off on the UN for being toothless, they're usually the same people would be first in line to push back on giving it teeth.
For example, I've personally known many people from a certain country (not America, although that probably applies too) that has a terrible human rights record, that has frequently gotten called out in the UN by fellow members. They'll roll their eyes and talk about how useless and toothless the UN is. But they don't want it to be more effective; in their case they have bad feelings towards the UN because of its complaints about their own country's human rights record. They can't or don't want to defend their country against those complaints, so their nationalism requires them to instead attack the messenger (the UN). And ironically, the very thing they attack it for is its inability to enforce its will on their own country.
Long story short, there's a lot of stuff to complain about when it comes to the UN, but anecdotally it sure seems like most of the complaints about its toothlessness comes from people who want it to go away altogether, not people who want to give it more teeth. I don't think I've ever heard anyone (including pro-UN people) argue that it should have more teeth or evolve into a supergovernment or anything. It always has been a forum and a means for governments to cooperate on shared interests, which is fine and is surely a good thing.