I'm annoyed that the FDA has kept cox-2 selective inhibitors restricted when the data I've seen shows they have lower GI risks and similar cardiovascular risks as other NSAIDs.
the process was also crazy complicated until some new 2020 legislation. the FDA published monographs saying things like "you can make a pain reliever with the following active ingredients and in the following forms." for example, no changes to the monographs on cough and cold medicines were made between 1987 and 2020. the new regime is of course a new mess to figure out, and consumers won't necessarily know the difference between a selective versus nonselective cox inhibitor. so you spend all this money and maybe inertia just keeps people buying ibuprofen and naproxen because it's what they know. and marketing something explicitly as "safer than ibuprofen" would be a massive hurdle to get cleared.
you can find all the FDA's monographs here, where it lists specific ingredients, concentrations, labeling, and testing procedures. https://dps.fda.gov/omuf/monographsearch